Lycosidae: wolf spiders

There are 37 British species belonging to this family. Lycosids or wolf spiders are medium to large species that are usually found running on the ground, although are burrow dwellers and others live near water, and can dive for safety. They are highly visual spiders, and have a pair of large eyes and then two small pairs in a row underneath and two middle sized ones on the side of the head. Most species are active during the day, with a strong tendency to bask in sunny spots in the open, often in large numbers in some species. When resting they fold their front legs underneath their body, and leave the rear legs stretched. When disturbed they can quickly run, even jump, for cover. They can be remarkably camouflaged in their habitats.

Courtship
Wolf Spiders typically mature in the spring. Adult males spend much of their time finding and courting females. They might locate the female first using pheromones, but the courtship display uses mainly visual cues. Male palps or front lets tend to be dark and males will wave them up and down alternatively, vibrating the palps and abdomen in front of females, legs stretched as in tiptoes, approaching a little bit in between signals. Females may accept the male by tapping their front legs rapidly on the ground, however they often retreat, or lunge at the males to scare them off. This rarely deters the insistent male for long. Read this post in BugBlog for more on the courtship of these spiders.

Mature male Pardosa sp. on the look out for females

A male courting an egg carrying female

Egg sacs and spiderling piggy backs
Their wandering nature has resulting on wolf spiders unique way to carry their egg sacs and their young. Females wrap their eggs in lentil shaped egg sacs that they secure to their spinnerets and carry with them for a couple of weeks. The female opens the egg sac to allow the spiderlings to emerge. Once they do, they climb onto their mothers abdomen and are so carried for several days.

Pardosa, likely amentata, a common species in my garden.

This is the bluest eggs sac I've seen on a Pardosa female. Possibly freshly made?

Pardosa female with her spiderlings

A wolf spider gallery

This family, as many other spider families, contains many species that are difficult to identify in the field. If you see any obvious identification mistakes please let me know.

Arctosa perita, an amazingly camouflaged species on sandy beaches and dunes (also top shot). This one photographed at Spurn Point yesterday. This species makes a silk lined burrow where she spends much of her time (read this post from Catherine Scott's blog with fantastic photos of this species and the burrows they make).

Possibly Pardosa pullata, female with egg sac, on rocky mountainside

Female Pardosa possibly amentata with egg sac, basking in the garden.

Unidentified wolf spider with spiderlings on mossy, heathland area.

Trochosa sp. on pond margin.

A Pirata piraticus, pirate wolf spider, resting on the water surface. This spider can be found on ponds and they often run across the surface, where they hunt small invertebrates.

The striking male Pardosa lugubris/saltans

Female Pardosa lugubris/saltans with egg sac

Semaphore flies

After a wildlife-packed June with the 30 days wild challenge, I felt like I needed a new focus and I decided to carry on a wildlife challenge by blogging/tweeting about an invertebrate I've seen that day for July. Yesterday, while walking by the local park pond I saw a Speckled Wood. The butterfly flew away, but it made me notice the flies dancing on the Colt's Foot leaves: they were Semaphore Flies, Poecilobothrus nobilitatus, a whole swarm of them signalling to each other. Although small, this species is very easy to identify by their smoky wings with a white tip. They are very active in July on muddy puddles and ponds.

Pair of red Mason Bees

While I was gardening, a furry, buzzing ball drops from the sky into the bottom of a clay pot full of broken crocks. I peek in: it is a pair of Red Mason Bees and the female, with the male firmly holding onto her back, has trouble climbing out. I give them a helping hand and place them on a dandelion. The female quickly starts to feed, greedily on the nectar. The male keeps holding on. He vibrates his wings making an audible buzz, drums with his antennae, kicks her abdomen and pushes with his head against the female's head. I know that Red Mason Bees do mate guarding, a behaviour by which the male 'piggy-backs' onto the female after mating to prevent her to be inseminated by a different male, allowing his sperm valuable time to fertilise the female's eggs. I have no way of knowing if they had already mated at the bottom of the pot, but the male's behaviour was far from a passive 'guarding': he was very busy indeed and oblivious to the food nearby. He carried on for a few more minutes and then flew away. The female fed for a while longer.
 You can watch a short clip here:

And now, ladies and gentlemen, spider sex!

I have seen spider courting behaviour on a few occasions, but the courtship was either too slow for me to watch the end of it, or the affair ended when the female captured the male and had him for lunch. Yesterday I was luckier, as I watched the common spider, Linyphia triangularis sequence of courtship and copulation. Let me warn you: spider sex is weird. Male spiders produce their sperm in testes inside their abdomen and insemination is internal, but instead of penises, they use their pedipalps - or palps - as an intromitent organ. This requires that before copulation takes place, the male transfers semen dropplets to reservoirs in his palps. This is a delicate operations: the male spins a tiny web and deposits a drop of semen onto it, then picking it up with the palps. Spider palps are a pair of modified appendages at the side of his mouth. In females and immature males, palps look like small legs. Once the male spider moults into adulthood, the palps appear fully developed, with a bulbous end and often a darker shade of colour than in the female. Palps have complex and diverse shapes, depending of the species, and are often used to identify male spiders. Palps have an additional function in some spiders, produce visual signal, as in jumping spiders and wolf spiders.
 Liniphya triangularis lives hanging belly up from its hammock-like web and courtship occurs at the end of summer, right after the female undergoes her final moult. The pair of Liniphia were actually mating when I saw them in a web in a Sedum plant, but a Siver Y moth disturbed them and they separated. The male then walked its way slowly across the web in search of the female. When he touched her, she moved a little further away, he then followed, touching her lightly every now and then. Once he faced her, she stayed still and accepted him by lowering her body at an angle, so that he could reach the underside of her abdomen, near the cephalothorax, where her genital opening is. He proceeded to insert one palp into her genital opening at a time, then the palp swelled as it locked with the females genital opening (above shot), and he removed it, appeared to lick it and then inserted the other palp. This was repeated on for quite a while as the male may need more than 100 intromissions to inseminate the female with two dropplets of sperm! The female was quite cooperative troughout and there were no signs of agression. She seems to touch the male's head with her chelicerae. Today they were still sharing the same web. Female normally only accepts a single male for copulation if he has completed sperm transfer, but this species has an alternative mating tactic in which smaller males interfere with mating and try and mate with the female (more here).
 I took two videos of the behaviour. The first one is a short sequence of the copulation itself, it the second, the pair, which has been disturbed, are separated and the male finds the female again and proceeds to carry on mating.





More information
Weldingh, Ditte Louise, Søren Toft, &; Ole Næsbye Larsen (2011). Mating duration and sperm precedence in the spider Linyphia triangularis Journal of Ethology, 61, 143-152 DOI: 10.1007/s10164-010-0237-x

Flies dancing on water

Approach a pond in July or August and crouch down. Focus on the surface of the water, checking the floating leaves or debris by the water edge and you will likely see jittery, shiny green flies. Get comfortable and watch them for a while, it takes some time until you can transport yourself to this small, alien world. These are long-legged flies, Poecilobothrus nobilitatus. They like to rest on floating objects or the mud on the edge (above), but they are also able to walk on the water surface. You will notice that some flies, the most active ones, have smoky wings with bright white wing tips - they are the males (top shot). Clusters of males may dance around single females, which lack the white wing marks (below).

Female walking on the water surface

To start courtship, the male focus on a female and approaches her, then he opens his wings in straight angles to his body and buzzes them quickly before closing them again, the wing-waving display, which is just a component of their complex and spectacular courtship. 

 Here several males circle a female wing waving, although the wings are barely visible as they are buzzing them. The three males court a female, which is watching the male in the right.

A male in the middle of wing waving

I took a little clip of their courtship earlier today.

The details of the courtship are a combination of wing waving and aerial acrobatics too fast for the human eye to follow, but they were described in detail by M.F. Land, which examined an hour of videos of courting flies in a pond in Sussex. The following figure from his paper represents the longest bout of filmed courtship, which was interrupted by the male chasing another male. Wing waving upon approach to a female is followed by hovering in front of her and flying over the female and back, and more wing waving. Courtship is often interrupted by chases to other males and then returns to the same female to carry on.

(from Land, 1993)

UPDATE: Thank you to Morgan Jackson for pointing out that this fly was one of the species in the Name a Species 2012 competition and won the lovely English name of Semaphore fly.

More information

Land, M.F. (1993). The visual control of courtship behaviour in the fly Poecilobothrus nobilitatus J Comp Physiol A, 173, 595-503 DOI: 10.1007/BF00197767

Hey, baby!

 Under the holly, on the leaf litter, wolf spiders (possibly Pardosa amentata) bask in the sun. Most females carry bulging egg sacs under their abdomens, while trying to find the best position to get warm. Several males move about, approaching a female with tentative steps, then tiptoeing, vibrating their front legs and black palps, and moving his palps alternating one up, the other down, as soon as he is very close (photo above).

The male from the top photo, gets a bit closer. This female is carrying an egg sac and snaps at him. 

He quickly retreats and starts stalking the next female... 

This one does not have an egg sac. Will he be lucky this time?

No, rejected again. A short moment of rest with the male and two females basking nearby

A female with a very large egg sac. The spiderlings must be close to emerge.

UPDATE 6/12/11: a little video taken on the day of one of the courting males: