Argiope revisited

After overwintering, the egg sac of the spider featured in this post has opened to reveal the hatched young. Few will make it to adulthood, and some of those which will, namely the males, will be devoured as a post-coital snack by the comparatively huge female.

Juveniles of Argiope lobata Pallas, 1772 - Siġġiewi

The species in question, Argiope lobata Pallas, 1772, is also being investigated as the source of the therapeutically useful toxins it produces to kill its prey.

Molecule of A. lobata's argiotoxin ArgTX-636, from Wikipedia

The photograph of the juvenile spiders comes courtesy of Mr. Patrick Tabone.

Sex! Murder! Cannibalism!

It looks like the blurb for some low-budget 70's horror flick, but such storylines are relatively commonplace in the arthropod world. Argiope lobata Pallas, 1772 is a spider displaying extreme sexual dimorphism - the small male is seldom seen, but the female is one of the largest arachnids found in the Maltese Islands.

As in some other arthropods of the sexually dimorphic ilk (e.g. praying mantises and crabs), the hapless male is frequently cannibalized by the female (seen in the pictures above) following mating. It is mainly seen in humid and shaded habitats suspended head downwards from its very strong web, patiently waiting for prey.

A hardy egg sac like the one below is subsequently constructed nearing the end of the summery season. Hundreds of small spiders hatch and spend the winter inside this sac, emerging in spring.

The images in this post come courtesy of Mr. David Dandria and Mr. Patrick Tabone.