essex naturalist

Invertebrates are probably not the most widely renowned for the investment of the parents in the well-being of their offspring. This is not, it seems reasonable to suggest, without good reason. That said, they will of course seek out what is deemed to be the best place location to deposit their eggs. A female dragonfly, for instance, may be drawn to a sufficiently weedy pond, while a hoverfly whose larvae attack aphids might seek out a likely looking plant on which to lay. But that is normally as far as parental responsibility in the invertebrate world often ends.

There are though, in the ever-intriguing world of nature, exceptions to what we may perceive as rules and perhaps more often than we might think. The chief inspiration here came from a recent encounter with the aptly named parent bug (Elasmucha grisea) in Thetford Forest. These shieldbugs are common over much of the UK, wherever birch is in adequate supply. On laying her eggs on a leaf the female will stand over them until they hatch, continuing her vigil until they grow to adulthood.

Parent Bug (Elasmucha grisea)

This got me to thinking about other parentally inclined insects and I recalled, a few years back, having idly rolled back a log whilst wandering through the woods, to finding an earwing (Forficula auricularia). It hadn’t scuttled away as most dark-dwelling creatures do when exposed to the light of day and I quickly discovered why. She (as it had now become obvious) was standing guard over her clutch of a few dozen, tiny eggs. She will dote over each of these little yellow pearls by licking them to keep them clean, for if she does not they might become contaminated with mould and fail to hatch.

Common Earwig (Forficula auricularia) guarding eggs.

A third, prominent example comes in the form of a spider, another creature found widely across the UK. The nursery-web spider (Pisaura mirabilis) is one of our larger, more noticebale species. They are hunting spiders and can often be seen resting on low vegetation, sensing for the movement of any potential prey to chase down and subdue. Like some other species (namely many of the wolf spiders) the female carries her clutch beneath her abdomen in a sperichal, white egg-sac. For her brood she constructs a tent-like web, often conspicuously bending over leaves in the process. Once the eggs hatch she then stands sentinel over her spiderlings on the surface of the nursery.

Nursery-web Spider (Pisaura mirabilis)