How do female dragonflies avoid male harassment?

After egg laying, female damselflies and dragonflies can be exposed to males trying to mate. Females will then be unreceptive and in order to avoid a lengthly and potentially costly copulation, they have evolved different strategies to avoid male harassment. These are only some of these strategies:

1) Avoiding water. This strategy appears to be quite general in the group. Males will return to the breeding ponds first after they mature and will be very obvious as they spend a lot of time patrolling the pond or sat on prominent perches, lake or river or hanging around near the water. In contrast, females often stay well away from the water, only returning to the breeding site to mate and oviposit. Staying away from the water allows females some control about when to mate.

2) Sneaking in. Females can be quite secretive when approaching an oviposition site, or they may lay during cloudy or cold weather - especially the larger species which can generate heat by whirring their flight muscles. Males are more likely to be roosting during dull weather or early in the morning, so females might be able to oviposit uninterrupted if they time their visit to the pond well.

3) Adopting an oviposition posture. If a male flies overhead, a female may try and repel him curving her abdomen down, like she was ovipositing. A great photo showing this behaviour in an Emperor female is here.

4) Looping the loop. Female dragonflies can fly faster than a chasing male, or do a loop the loop or even dive under water to avoid harassing males!

5) Androchromes. In many damselflies, such as the Blue-tailed and the Common Blue damselflies there is genetic variation in female colour with some of the colour forms strongly resembling males. I have covered this topic recently in Blue-tailed Damselflies.

A female Emperor with a very blue abdomen (16/07/2018). 

6) Age-related male mimicry? Females have an ability to store sperm and the sperm from a single mating should be enough to fertilise all her eggs for two weeks. In some species of dragonflies, females change as they age to resemble males (e.g. Emperor, Common Darter). The abdomen of mature female emperors is green, but it may turn blue - like a male's- when they are about 2 weeks old (it is unclear, however, it this is a purely age effect or a temperature response to warmer weather as the season progresses). If this was age-related, then male mimicry might reflect a different evolutionary response to the same selective factor than the genetic androchromes. When the female is young it is in her interest to attract males and mate, but as she ages she is likely to have already mated and the colour change might make it easier to avoid male attention. More research is definitely needed!

7) Playing dead. One of the most striking strategy of male avoidance is that of the Common (or Moorland) Hawker Aeshna cyanea (top shot). Ovipositing females often chose sheltered spots with denser vegetation in ponds to avoid male detection. As females leave ponds after ovipositing, males chase them. Rassim Kheliffa carefully documented that in such occasions, females dived into the tall grass surrounding the pond, staying motionless, often upside down, and so avoiding being grabbed by the males. The females were alert and responsive, and 87% (out of 31 attempts) where able to successfully avoid being picked by Rassim. He hypothesised that death feigning has evolved by females co-opting a pre-existing antipredator behaviour into a male avoidance strategy to avoid undesired mating attempts

More information
Corbet, P. S. The Life-History of the Emperor Dragonfly Anax imperator Leach (Odonata: Aeshnidae). J. Anim. Ecol. 26, 1–69 (1957).
Khelifa, R. Faking death to avoid male coercion: extreme sexual conflict resolution in a dragonfly. Ecology 98, 1724–1726 (2017).

Credit: Top photo of Common Hawker by Robert, used with permission.

Why do male Wool-carder bees defend a flower patch?

I found the first male Wool Carder Bee, Anthidium manicatum of the year in the garden today, patrolling and basking on the large sage patch that is a favourite if many species of bee. If you have a flower-rich garden with a sunny aspect, chances are that in warm, sunny summer days you will see this chunky bee attacking other flower visitors, including large bumblebees. Male bees from most bee species often just hang around nests where they can mate as females emerge, or patrol flowers favoured by females. Occasionally they 'jump' onto or chase other bees or insects, possibly checking if they are females. For example, Male Hairy-footed flower bees, Anthophora plumipes, who emerge a week or so before females, will jump onto bluebottles, the only insect that roughly resemble the black females of his species. No other male bee is as aggressive actively defending a patch of flowers as Wool carder bees. They even have sharp spines at the end of their abdomen with they can use to harm, or even kill, other bees, so they rapidly become the only bees using the flowers

The abdominal spines of male Wool carder bees

 Most female bees mate once shortly after emergence, so males only had a chance of mating successfully early in the season. Females store the sperm of this early mating and use it to fertilise their eggs throughout the nesting season. Females will repel or avoid courting males vigorously once they've been mated. In contrast, Wool-carder bees are unusual in that females both mate multiple times and accept matings throughout their flight season. Witnessing solitary bees mating is quite rare, but with Wool carder bees, matings are quite frequent. Many females visiting a defended flower patch will mate with the resident male. The male defending a good flower patch will likely gain many matings with several visiting females, but, given what we know about sperm usage in solitary bees, will he benefit from fathering the female's offspring?

Mating Wool carder bees

 In a recent study, Kathrin Lampert and colleagues from Ruhr-University Bochum carried out some experiments to investigate why Wool Carder bee mating behaviour is so different from other bees. They in particular were interested in testing the hypothesis that Wool-carder bees might show what is known as 'late male sperm preference' in which the last male mating with a female has a disproportionally higher chance of fathering the females offspring.
 To find out 'who is the daddy' they used genetic testing in a similar way to how paternity is tested in humans, using genetic markers that have many variants, and therefore are likely to be different between individuals. In order to be able to capture the likely mothers and fathers of particular nests they constructed large flight cages containing Betony plants (for pollen and nectar) and Stachys byzantina (for plant wool, which the females collect to line their nest cells). Wool carder bees nest readily in sections of bamboo sticks, and they fixed artificial nesting sites inside the flight cages. Offspring of a female are found in a linear nest in consecutive order, the deeper cells in the bamboo stick contain the earlier laid eggs, while the cells closer to the entrance contain the later brood, which is likely to be male offspring. They carried out three experiments, in the first one, to test the feasibility of these experiments wild males and females (likely to have mated before) were captured, individually labelled with a dot of paint in the thorax, and released in the flight cage. In the second experiment, males in the cage were swapped to test if males with later access to females would father offspring. In the third experiment males were removed after a few days and females left to nest with no males, to investigate if females are able to store sperm. After the females had completed their nests in all the experiments, DNA samples were taken from the males and females, and them and the offspring found in the artificial nests screened for genetic paternity analyses.
A problem with their experiment were cleptoparasitic wasps, which destroyed the bee larvae and prevented genotyping. Another problem, which stems from bee's sex determination system, is that only female offspring have a dad: males develop from unfertilised eggs, so they only have a mum. They could only find out if offspring were male or female after genetic screening. Despite this, they obtained a number of female offspring from many females.
 The results revealed that the males flying with females at the time the females were provisioning a cell, where they are close to laying the egg, were the most likely fathers of the offspring (84% of the time), whereas most of the remaining fathers were males present in the cage in previous days, supporting the hypothesis of late male sperm preference. Males that were dominant, that is, chased away other males from flowers, tended to father more offspring, as most matings happened on flowers.
 The male removal experiment showed that females were able to store sperm for at least 11 days, and possibly much longer.
 This research suggests that a predisposition for late male sperm precedence in the ancestors of wool carder bees might have been what favoured the aggressive territorial behaviour seen in males, as they can benefit from monopolising floral resources visited by females.

More information
Lampert, K. P., Pasternak, V., Brand, P., Tollrian, R., Leese, F., & Eltz, T. (2014). ‘Late’male sperm precedence in polyandrous wool-carder bees and the evolution of male resource defence in Hymenoptera. Animal Behaviour, 90, 211-217.

Wandering male lace weavers

In the last week I have found two different males Amaurobius similis wandering, one in the porch and the other in the house. Note the different abdominal pattern in the photos below, especially the dark blotches surrounding the cardiac mark (the midline elongated area over the abdomen). In this species, mature males are most likely to be found between September and November, and they abandon their webs in search of the female retreats. I released them both after taking their photo paying especial attention to the palp (above), which is diagnostic and separates this species from the similar one A. fenestralis. Males A. similis have an inward pointing, curved sharp projection on its palp, which in A. fenestralis is thicker and blunt.

Male 10/11/15.

Male 15/11/15.

The patrolling Red Admiral

Since the beginning of June, Red Admirals have been well established, having returned from the Mediterranean in their one way spring migration. Females should be mating and looking for sunny nettle patches in which to lay their eggs. Males should be looking for receptive females to mate with. They will produce one or more broods in the summer. As temperatures drop in the autumn, butterflies will prepared themselves for the autumn migration and then they become very apparent in gardens, where they feed on buddleia and other nectar rich flowers. Male and female have the same wing colour pattern. If you have a good view of the abdomen when the butterfly is resting with its wings open, a swollen abdomen will allow you to identify a female, but otherwise it might be easier to tell them apart by their behaviour in early summer.
 Last week, in the afternoon, I have flushed a Red Admiral from the same sunny spot on a grassy area amongst trees, where they were sitting day after day, exactly where I often found them last year. This afternoon was unusually warm and, as I left work, a Red Admiral sat on a low hedge on a wooded glade teeming with nettles in our university campus (above). It would sit and then fly up patrolling around the trees and chasing passing bumblebees in a similar way a Speckled Wood male would do, and then return to the same perch. I had never noticed this behaviour in the Red Admiral, but it appears that I had observed a male, and that red Admiral males actually defend territories. It might seem hard to believe that beautiful, fluttery butterflies actually engage in any kind of aggressive interaction. Indeed, butterflies have no offensive weapons other than their wings, and, butterfly contests, even when they are defending a territory are often perceived as chases instead of aggressive interactions. However, there is now abundant research showing territorial behaviour in a number of butterfly species. The important point is not the presence of an actual fight but the outcome: as a result of the behaviour the owner remains in the territory and the intruder flies away. Royce Bitzer and Kenneth Shaw studied the territorial behaviour of the Red Admiral on the Iowa University campus. They captured and marked individual Red Admirals with different spots of paint and observed their behaviour once released. They found that Red Admirals spend the morning feeding, but each evening males establish temporary territories for a couple of hours before roosting. Males spent most of their time perched, but occasionally patrolled their territory boundaries. They were not seen feeding. Birds or other butterfly species were chased in a linear way, but male intruders are chased upwards in a spiral. In Red Admiral chases, the owner often retains ownership and the intruder flies away. Good territories are likely to be an area containing resting spots from where passing females can be easily detected, usually with linear features (e.g. a pavement or a few trees in a line). The maintenance of these temporary territories could allow better access to receptive females moving into their roost, as mating is thought to happen in the roosting sites in trees.

A particularly bright red and intact individual, maybe the result of a first local brood?

Two days later a much more faded individual with tattered wings, on the same favoured spot on the grass.

More information
Red Admiral and Painted Lady Research Site. Here.

Bitzer, R. J., & Shaw, K. C. (1979). Territorial Behavior of the Red Admiral, Vanessa atalanta (L.)(Lepidoptera: Nymphalidae). Journal of Research on the Lepidoptera, 18(1), 36-49. here.

Male garden spiders out on a mission

Even my four year old has noticed that there are lots of spiders about. She found many fresh webs by Araneus diadematus today, and she asked why are there so many now. I tried to explain that they have grown large recently, and that's why we are seeing them more easily, but she discarded this and came up with her own explanation: is her watering the plants yesterday what must have made them grow. Female Araneus diadematus are reaching quite large sizes now, although there is a lot of size variation. The record holder in our garden sits by two rubbish bins, and has probably been gorging on the flies the rubbish attracts. Males have also reached adulthood and, in contrast to the sit-and-wait females, are moving between bushes in search of receptive females. I have come across three in the last few days. They have slimmer abdomens and robust legs and their palps are quite noticeable. The male must be careful, though, as females will quickly make a meal of him if he does not reach their high standards. I found this male getting closer to a small female's web. As he was on a broom, focusing him was very tricky and I resorted to trying the white bowl.

The end of the affair

As the solitary bee herald of spring, Anthophora plumipes, is my favourite bee. It is with some sadness I found this dead male on the path today. The rain might have contributed to its demise, but it might also have reached the end of its natural life. In my patch, the first males appear at the beginning of March, and the last males, usually worn individuals, fly until the middle of May, barely two months of male activity, but the lives of individual males are bound to be even shorter, something I was referring to in my last post. On the bright side, the females will be still busy nesting for another month

Red Mason bee male checking out Melecta

A Melecta albifrons male has been feeding lazily on the Erysimum in the afternoon a sunny day.  Clambering over the flowers, not bothering to fly, this cleptoparasitic bee behaves in a very different way to its host: the buzzing, hovering, always alert Anthophora plumipes. Red Mason bee (Osmia rufa) males are patrolling the flowers and they check everything vaguely looking like a Red Mason bee female. With their contact, they scare away females A. plumipes - which I guess feel harassed like they do when their own males jump on them. A male Osmia rufa sees the Melecta and jumps on it. Just a quick contact, presumably chemical cues are checked and if not right, the bee flies away. The Melecta stays on. And when I check the camera, I am thrilled I got the shot!

Melecta albifrons male (photos 26/03/2012). They are handsome bees.

Early wool carder bees

This year much buglife has been appearing earlier in the season than last. Wool carder bees haven't bucked the trend and I saw the first male, yesterday, large, aggressive and bossy from the start, patrolling the sunny herb patch in my local Wildlife Garden. I came back today for more bee watching and better shots and females were also out. The main object of the resident male's attentions is a patch of Hedge Woundwort, Stachys sylvatica, a native plant close relative of Lambs ears, S. byzantina. Both are hairy plants of the mint family, the native one less so, and so favoured as food and wool plants by the female Wool Carder bee. The male knocked a bumblebee down to the ground and proceeded to watch a female while she fed, and attempted mating. He followed the female closely around the Stachys patch, hovering a few inches behind her (above). When she left, he moved around the patch, hovering in places, changing his body orientation, watching every moving thing that dared approach his newly founded chiefdom. He stopped to rest on a sunny leaf every now and then, all the time watching, vigilant.

The female feeds on Stachys sylvatica

Male Wool Carder bee resting

Racing male tree bumblebees

In the last two weeks, the garden has been overtaken by frenzied male bumblebees. They follow a set circuit, round and round, racing from bush to bush and then having a little bumble in each. If you wait for a bit on a particular spot on the route, you are likely to see another bumblebee a few minutes later passing by in the same direction, doing exactly the same. Most of the males I have been able to identify doing this are Bombus hypnorum. Today, a male B. hypnorum - which can be distinguished from the female by his white moustache - got trapped inside the conservatory and I had his portrait taken (above). Many male bumblebees have recently emerged from their nests, never to return, and their mission is to find queens and mate with as many as possible. In many bumblebee species, males' strategy consists on tracing a route, sometimes hundreds of meters long, often circular, depending on the species, and marking certain places along the route with pheromones produced by scent glands in their jaws. Males join already set routes and therefore many males, some of them probably their siblings, go round the same routes every day, stopping to feed occasionally. Queens encountering a route are attracted by the pheromone and are then intercepted by males. The discovery and first description of these male bumblebee flight paths - from Bombus hortorum males - dates back to Charles Darwin, from observations he carried out at Down House. Although he didn't realise pheromones were involved, he noticed bumblebee routes and them stopping and bumbling at places he called "buzzing places", and marveled at the fact that the same or very similar routes were used year after year:

I then followed their route for about a hundred and fifty yards until they came to a tall ash, and all along this line they buzzed at various fixed spots. At the far end, near a pollard oak, the track divided into two as shown in the plan. On some days all the bees flew in the direction I have described, but on others some arrived from the opposite direction. From observations made on favourable days, I think that the majority of individuals must fly in a wide circle. They stop every now and then to suck at flowers. I confirmed that whilst in flight they move at about ten miles an hour, but they lose a considerable amount of time at the buzzing places. The routes remain the same for a considerable time, and the buzzing places are fixed within an inch. I was able to prove this by stationing five or six of my children each close to a buzzing place, and telling the one farthest away to shout out " here is a bee " as soon as one was buzzing around. The others followed this up, so that the same cry of " here is a bee " was passed on from child to child without interruption until the bees reached the buzzing place where I myself was standing.

  This sketch of the grounds of Down House shows the part of the male bumblebee flight route studied by Darwin with the help of his children. What fun must have been to have him as a dad!

References

Freeman, R.B. (1968). Charles Darwin on the routes of male bumblebees. BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) HISTORICAL SERIES , 3 (6), 177-189.


Stiles, Edmund W. (1976). Comparison of Male Bumblebee Flight Paths: temperate and tropical. Journal of the Kansas Entomological Society., 49 (2), 266-274.

Spider chat up lines

In summer and autumn, spiders become more noticeable. The tiny spiderlings born in the spring have now become adults and males are wandering in search of females. One of the most common spider species in the UK is the elegantly marked Linyphia triangularis (female above). This spider makes a sheet web with criss-crossing silk lines over it in low bushes and trees. The spider hangs belly up from the underneath the sheet. Flying insects colliding with the transversal lines  fall onto the sheet, where the spider traps them. Yesterday, while photographing 7-spot ladybirds I came across a pair of L. triangularis. The male made jerky movements with its chelicerae and palps and the female replied.

Male (on the left) and female Linyphia triangularis. Note the male's large fangs on the bottom photo.

Unfortunately, I seemed to have disturbed them and the male retreated, so I didn't see the end of the interaction. Field experiments carried out by Nielsen and Toft showed that male L. triangularis use what are known as 'alternative mating tactics'. Males guard subadult females just prior to their final molt in order to access them while they are still virgin, possibly due to a strong sperm preference which results in males mating with a virgin female fathering most of the female's subsequent offspring. These researchers took advantage of this behaviour and took 56 males and paired them with females in the field. Once this relationship was established they introduced an 'intruder' and recorded what happened up to the point when the female was mated. In 64% of the cases, the males resolved the dispute about the female by fighting using their large chelicerae. Larger males are better at winning these direct conflicts. But in 36% of cases, males used a different strategy called 'interference'. After losing a fight, they hang around and 'distract' the courting pair trying to chase the winning male away from the web. They actually succeeded and mated the female first in 7 occasions (12% of all conflicts) showing that this strategy - which is adopted by small males - can pay off. Additional observations suggest that smaller males hang around and try and mate with the female (not virgin at this stage) probably winning some residual paternity in the process.

 In a different study, Funke and Huber carried out detailed measurements of males and females genitalia and cheliceae (see figure above) and found out that male chelicerae (including the oversized fangs) grow faster with body size than genitalia, indicating strong directional natural selection on this trait due to the large effect on male-male conflict in their fights for females.

More information
S. Funke and B. A. Huber (2005). Allometry of Genitalia and Fighting Structures in Linyphia triangularis (Araneae, Linyphiidae) Journal of Arachnology, 870-872 DOI: 10.1636/S04-16.1

Nielsen, N and Toft, S (1990). Alternative male mating strategies in Linyphia triangularis (Araneae, Linyphiidae). Acta Zoologica Fennica

A pair of Hairy-Footed flower bees

On the sides of a little cul-de-sac near University there is a patch of Comfrey. Last year it attracted several species of bumblebees (B. pascuorum, B. pratorum and B. hypnorum) and bees (Anthophora plumipes), which love their dangling flowers. Since the plants started to flower mid April I cannot resist to stop for a few minutes on my way to work. The strategy paid a few days ago, when two A. plumipes were in the patch. The female fed on the flowers while the male went about in his patrolling flight around the clump. Then, the male caught sight of the female and hovered behind her.

A female Anthophora plumipes feeding while a male hovers just behind her.

Now, I must apologize that last year I wrote a post entitled 'Anthophora plumipes: a final post (I promise)'. If you follow this blog you'll realise I have broken the promise several times: I am just unable to stop posting on this little bee.

Red Mason bee male tactics

I posted about the Red Mason Bees (Osmia rufa) nesting in our bee post last year. The males  have now been active for a few weeks, and they are quite interesting to watch, as they are very inquisitive and interactive with other insects. The different behaviours of male bees depend to some extent on how the resources used by females - such as nesting sites and food plants - are distributed. These resources indicate where females are to be found, and to maximise their reproduction males are to encounter and mate with as many recently emerged females as possible. In Osmia rufa, females are thought to mate only once shortly after emerging from their nest, as males guard females after mating and impregnate them with chemicals that make the females unattractive to other males, effectively ensuring their paternity. As many other bee species, Red Mason Bees are polylectic - they are quite generalistic as to what flower species they feed on - and their nests are quite scattered (at least in natural habitats!), and therefore it does not pay to be territorial. In a 1988 paper I read today, Karsten Seidelmann graphically described Red Mason Bee behaviour based on 364 individually marked males:

In order to find mates, each male roamed about his home range. These home ranges were located around flowering groups of foods plants, but also by nesting places. Occasionally sunny places (exposed leaves, stones, etc.) or bushes of dwarf pine in the surrounding of large nest aggregations were inspected and patrolled as well. Home ranges sometimes also consisted of several small patchy encounter sites. Males then searched within the patches and flew in a straight line between them. Every home range contained an exposed sunny place where the resident male basked between patrol flights at irregular intervals. When home ranges become shadowed, males turned to other areas, returning when the area was in the sun again. Areas abandoned because of shadows were not occupied by other males.


The photo heading this post shows a male next to a potential nesting hole in our bee post. The males often enter and inspect the holes and look out.
These little bees often chase and make contact with other bees - not only of their own species but also other insects such as butterflies in their home range - and I had misinterpreted this behaviour as agressive, an indication of territorial behaviour. Seidelman's detailed observations, on the contrary, shows that the Red Mason Bee is not territorial. It does have a 'home range' but these are not exclusive to one individual and home ranges of different males partially or totally overlap. Males also occasionally went on 'excursions' away of their home range. Their chasing and making contact with other visually detected insects is an 'inspection' behaviour: they check if they are conspecific females or not, but they do not attempt to drive them away:

Home ranges ranged from 3 to 30 m2 in size. Males continuously altered their home ranges in response to changes in possible encounter sites. Plants that started to flower were integrated in adjacent home ranges, or new home ranges were established and old ones were abandoned. If females emerged from a large aggregation of nests, the searching activities of several males were concentrated entirely on these nesting places, with males inspecting nest entrances frequently.
Males inspected all resting and flying insects with an O. rufa-like shape during their patrol flights. They approached other solitary bees (e.g., Osmia, Megachile, Anthophora, Andrena), as well as honeybees (Apis), bumblebees (Bombus), or even flies (e.g., Calliphora). However, only receptive females of their own species were mounted, whereas males of O. rufa and other insects were abandoned immediately after a short contact.


Seidelman also analysed the reproductive success of males, that is, how many times they mated throughout their lives and concluded that this is independent of the male body size.

More information at:
Karsten Seidelmann (1999) The Race for Females: The Mating System of the Red Mason Bee, Osmia rufa (L.) (Hymenoptera: Megachilidae). Journal of Insect Behavior, Vol. 12:13-25. here.

Robert John Paxton (2005) Male mating behaviour and mating systems of bees: an overview. Apidologie 36:145–156. here.

At close range

If a neighbour had casually seen me on my garden this morning, he or she could have rightly thought either that I was out of my mind or that I was practicing some tai-chi. But no, in one of the few sunny spells we had on an otherwise windy, cold morning, an Anthophora plumipes male stopped to sunbathe for a bit longer than usual. It is the longest time I have seen one of these fast high-pitched buzzing bees sitting still. The spot was quite near to the wall where I photographed the male in yesterday's post, possibly the same individual, but the background was much more interesting and I wanted to get a closer picture. Unfortunately, a barrier of lavenders, plum branches and primroses separated me from my subject, so I had to stretch and contort, while supporting myself with one hand on the mud, moving very slowly to take this photo one-handed. I just cannot hold it for a future post, as it is since now my favourite A. plumipes male photo. After a few minutes, the male started looking around nervously, flicking his antennae and, having warmed up, flew away.

Anthophora plumipes is back!

Yesterday it was the equinox, so it is finally spring. We had a sunny mild day today and from first thing in the morning we've had a couple of Anthophora plumipes males patrolling in the garden. I saw the first male of the year on the 17th of March, but it was too fleeting a sight and he did not stop. Today I managed a few shots during the few seconds one of the males Anthophora stopped to rest on a wall. You can see their forward-pointing middle legs, with the plumes of hairs that give them their name. These bees - as honey bees and bumblebees - are extremely endothermic, that is, they are able to increase their body temperature with respect to their environment and this allows them high activity levels at temperatures where other insects just sunbathe to increase their body temperature. Experiments by Graham Stone and colleagues have studied the ability of A. plumipes to increase their internal temperature. Accordingly, at the 8 degrees in which bees were active this morning, their body temperature is likely to have been around 28oC. The males patrolled constantly in a route around the garden and occasionally stopped to feed in some small Daffodils and Primroses. Males always emerge first from the nest where they were born, followed by the females. This is so because in the long tunnels where females nest, they lay fertilised eggs first (which will become females) and the last ones unfertilised (which will become males) and the bees emerge in reverse order of laying as the last eggs laid are closer to the opening.

Watch out! Tegenaria males about

It's that time of year again. Come early autumn, large, long-legged, fast spiders take you by surprise crawling across the living room, or alongside skirting boards or, better still, greeting you when you are getting in the bath - where they have fallen the previous night. They are house spiders from the genus Tegenaria. It is not a large genus, with only 11 species in Northern Europe, but they include the largest spider in the UK, the Cardinal spider Tegenaria parietina, which can reach 14 cm across its legs (see the proof here). Tegenaria are remarkably difficult to identify to species level, something I find quite frustrating. Forget about it with the females (unless you capture them and closely examine their genitalia). Even with relatively close shots of male palps identification is difficult. You have to content yourself with Tegenaria sp. Females usually keep to their web on hidden, dusty corners around houses or under beds. The wandering house spiders of the autumn are actually males in search of females.

This one stayed on a skirting board for a whole day a few days ago.
I got a close shot of the palps of this other male, three years ago to the day.

New males on the block

I have spent a good couple of hours crouching next to my Stachys plant, camera in hand, fascinated by the drama rapidly unfolding around it. And the news is, that the first Wool Carder bee males appeared today. Early in the morning the females (at least three of them) were feeding and gathering wool in their usual way, when one individual started chasing around others. I checked and, yes, it was a male. A beautifully fresh one (pictured above). It gave the impression to rest occasionally on a leaf or stick, but on close inspection he was moving his head incessantly, visually scanning around looking for potential 'illegal' users of his newly declared kingdom. Since the Stachys started flowering on the 11th of June at least three bee species have been more or less regularly feeding on the Stachys. Bombus pascuorum the most common one, then Apis mellifera, the Honey Bee and occasionally Bombus terrestris. Now they are under attack. Attacks today were not very often and the I didn't see any matings, but maybe it's because is the first day. A honey bee was quite persistent and came back several times after being pounced upon by the male. The male moved between the Stachys and the Phlomis, and I managed to see both a male and a female feeding on the Phlomis, the male after a few tentative tries, managed to push the flower open and feed. The female in search of pollen, lifting the upper lip of the flower to expose the anthers. Wool-Carder bees have a special attraction for Lamiate plants (the mint family) and these are the only two flowering in my garden at the moment. The sage and the lavender are not in bloom as yet. After a while I noticed there was a second male. It looked like it was covered in dust, but when I checked the photos they were actually mites! I saw females with mites too, especially around their 'waist'. The male seemed to be a bit bothered by it and keep trying to clean his head. This actually makes both males - if there are not more - easy to tell apart. You can see from the photos.

Honey bee

A sorry-looking male covered in mites

On this shot the density of the mites is very apparent on the same male. The male

 was pushing his way into a Phlomis flower.

And before leaving Wool Carder Bees - for now! - I recently came across a fascinating site, the Biodiversity Heritage Library, a formidable project by which 10 world-leading institutions, including the Natural History Museum and Kew Gardens, are to digitize their library collections. The site now includes over 13,000 books and journals scanned and freely available to download to everyone. It is also fully searchable. It has now become my favourite site to find out old literature about a species - the type that is not usually available in your typical university library. In this site I came across this beautiful drawing of Wool Carder bees, illustrating the size differences between males and females. The illustration is taken from "The Cambridge Natural History", ed. by S.F. Harmer and A.E. Shipley, v 6.

Anthidium manicatum, the Wool-Carder Bee. A, male, B, female.

Wool-Carder Bee watching 1: Male watching

The Wool-Carder Bee (Anthidium manicatum) is one of the most fascinating bees to watch in my garden. They are handsome bees, quite robust, with white-haired legs and brown hair on the body and stark yellow and black markings in the face and abdomen. Unlike most bees, Anthidium males are larger than females. The first Wool-Carder Bees appear in June. The males are territorial and defend a patch of flowers - frequented by females - with constant patrolling, and aggressively chase off or attack any intruders that pretend to 'steal' their nectar and pollen. It has been reported that they have killed other bees or bumblebees or rendered then unable to fly. Males have five pointed spines at the end of their abdomens with which they try and pierce other insects. The resident male flies when in patrol and hovers momentarily facing any possible insect, in most cases, the other bees flee when chased by the resident male. The males are most active in the middle of the day, resting on the early morning and late afternoon, often on a flower, holding on characteristically with his jaws. On this time, the other bees can forage in peace.

Male resting on Lavender

When the male notices a female in his territory he approaches and hovers behind her, waiting until she is feeding to jump on her and mate. Sometimes the male just approaches and seem to touch the female and leave her alone to feed.

Wool-Carder bees copulating on Lavender. In this photo the larger size of the male is obvious

Wool Carder bees have relatively long tongues (7.5-8.5 mm) and like deep flowers such as Lavender, Jerusalem Sage (Phlomis), Woundwort (Stachys), Tree Germander (Teucrium) and Sage (Salvia officinalis). Mating often takes place on these flowers.

Male feeding on Stachys byzantina or Lambs' ear

 Research by Severinghaus and coworkers on American populations has shown that male Wool-Carder bees follow two strategies to secure access to females. Larger males are territorial and mate with females feeding or gathering wool from their patch. Smaller males are 'wanderers' and sneak on resident male territories to mate with foraging females. This research, following marked bees on two summers, uncovered a remarkable level of turnover in territory ownership, with most territory ownerships lasting less than 4 days (the maximum was 30 days).
 In my garden, a male often rested on Jerusalem sage. Possibly the same male that ended up being a meal for a spider that lived on the same plant.

Male resting on Jerusalem Sage flower

Enoplognatha ovata has just captured the male