Monday, 20 May 2013

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:

Sunday, 19 May 2013

Wolf spiders with egg sacs

Suring a sunny spell, the first wolf spider of the year carrying an egg sac - likely to be Pardosa amentata - run across the warm concrete in the garden. The silk on the egg sac was still bluish, indicating that it was very fresh. A little later I found another one sunbathing on the conservatory frame (below). A male kept approaching in full courting display mode, but she quickly lunged at him and retreated like saying 'go away, you are wasting your time'.
 Female wolf spiders as many other spiders display maternal behaviour. First, they carry their eggs wrapped in a silky egg sac until their spiderlings emerge. As these spiders move about in search of prey, this offers more protection to their eggs from casual predators than if the egg sac was attached somewhere and left on its own. Then, they open the sac when spiderligst are ready to hatch and allows them to climb on her back. The spiderlings will ride their mum for a few days before dispersing. These are sun-loving spiders, actively moving to and from sunny spots to adjust their temperature to higher than the ambient temperature in a similar way to lizards. Being carried about by their mother - both eggs and young - is likely to serve thermoregulation purposes, optimising the speed of egg and young development, as females of some Pardosa species have been shown to prefer higher temperatures than males and immatures.
Basking female.
Despite the mother's best efforts, wolf spider's egg sacs are often parasitized by tiny often flightless ant-looking wasps of the genus Gelis. Read this post by Chris Buddle to find out first hand about wolf spider egg parasites.
A Gelis wasp runs on the blue bin lid.

Click here for more wolf spider posts in BugBlog.

Thursday, 16 May 2013

Egg laying Footballer hoverfly

Footballer hoverflies are commonly seen near water: ditches, ponds and drains, their genus name Helophilus, actually means 'lover of marshes' in Greek. On a little twig over a puddle on the pavement by a busy road, two Helophilus pendulus females - their abdomens large and turgid with eggs - laid. While one of them was busy actually laying under the twig, the other seemed to be 'feeling' the twig with the ovipositor, probably selecting the best site to lay her shiny white eggs. Note the ovipositor stretched out. Helophilus lay their eggs on clumps - like bluebottles - unlike other hoveflies which lay individual eggs singly. This might well be due to their different feeding habits. Many hoverfly larvae are predatory, and being born away from hungry siblings might give them a better chance to find food (like aphids). Helophilus are related to Droneflies, and their larvae, called rat-tailed maggots, are aquatic, and develop on very wet manure or submerged rotting organic material often in large numbers, so they are less likely to compete for food. Their 'tails' are actually long telescopic breathing tubes, that they can retract into their bodies.
 For a great series of shots of Helophilus egg laying and larvae development check BugGuide.
Another shot of the laying female
I turned the twig to reveal the egg clutch after the female lad left. As they lay under the twig, the eggs are not readily visible.

Sunday, 12 May 2013


A rainy day, I look around the house for things to look up with the little digital microscope and I find the shrivelled shell of a spider, probably a Tegenaria, in the conservatory, behind a pot. I notice the fangs and look under the microscope. It is not the best photo, but I am quite pleased with the fact that the tiny openings at the end of the fangs (where the venom comes out) are just visible. Click here for a scanning electron photograph of these openings. The fangs act as hypodermic needles, injecting the venom inside the prey's body. The teeth that help hold the prey while the venom is injected are visible at the bottom.

Adult pair of Pholcus phalangioides

 In the last few days, I have been keeping an eye on a pair of Pholcus phalangioides in my outside toilet. They are a male and a female, and given that both appear to be adults I guess the male is waiting for the female to become receptive. I got a close up of the male, showing its almost circular caparace and its palps (above).
Pholcus phalangioides. Male on the right, not its elongated abdomen. 

Tuesday, 7 May 2013

Black Lace Weaver: the female

Not even a week after finding my first male Black Lace Weaver, Amaurobius ferox, I came across the beautiful female by the back door mat of some relatives. The previous day I had seen a very fresh dead, limp male - which now I believe had just had a fatal encounter with the female - and possibly disturbed the female from feeding on its corpse. I checked the palps and left the corpse where I found it. The following day, on the same place where I had found the dead body of the male, I spotted the female, indoors. I took more photos of her, velvety black, fresh, alert. She moved across the room in broad daylight, and fearing for her life, I took her outside to a safer place.
A view of the top of the female, showing how dark it is and the faint markings of her abdomen
Crouching by a chair leg
A 'habitat' shot
Later, I spotted the body of the male, this time wrapped in cribellate silk, its skin empty like a discarded sweet wrapper. Were both wandering in search of mates, what was she doing out in the daylight, far from her hiding hole?