Lepidoptera – Page 27 – David Bradley

What to do if you find a toxic moth nest

As a keen photographer, I am always on the look out for odd and intriguing things to photograph. In the absence of birds other than skylarks and rooks along the St Ives to Cambridge guided busway I photographed what looked like a silky nest in a blackthorn/hawthorn bush. It was on the left-hand side of the walkway as you approach the Oakington stop (about 400m away in fact). And then another.

I posted the photo to Facebook and asked for comments (to be honest I hadn’t even noticed the caterpillars at the time I took the photo and only did so when I was “developing the print”. I had been musing on it being an immigrant funnel web spider’s nest or similar and keeping my distance.

Singing friend Jill Barrett suggested the caterpillars were those of the oak processionary moth (Thaumetopoea processionea). This species has been causing problems for oaks for a number of years, but it seems infestations were, until recent years, limited to London and environs. Graham Bellamy commented that it was more likely to be a Brown-tail moth given that the nest was growing on a thorn bush rather than an oak tree. This was later confirmed by a contact at the Forestry Commission.

If the Forestry Commission had said these were oak processionaries, that wouldn’t have been good news for our local oaks. It would also have been bad news for anyone who comes into contact with these caterpillars. They have myriad tiny hairs which if they touch skin or eyes or fragments are breathed in can sometimes cause serious inflammation [and irritation of skin, eyes, and lungs].

If you see one of these nests, stay well clear. Don’t try and remove it yourself even if there are no live caterpillars present, there will inevitably be toxic hairs and hair particles left behind. There are many species of hairy caterpillar that can cause similar health problems and there are others that damage different trees.

Here’s the science bit:

The oak processionary moth caterpillar hairs carry lots of soluble proteins, one of those extracted and identified in 1986 is found only in the hairs and causes a reaction on skin identical to that produced by contact with the hairs and so is assumed to be the causative toxin of the inflammatory response. Texier et al named this urticating protein thaumetopoein. It is, they explain, formed from two protein subunits and is present in large quantities in the glands producing the caterpillar's urticating hairs.

“Thaumetopoein: an urticating protein from the hairs and integument of the pine processionary caterpillar (Thaumetopoea pityocampa Schiff., Lepidoptera, Thaumetopoeidae)” by Lamy M, Pastureaud MH, Novak F, Ducombs G, Vincendeau P, Maleville J, Texier L. in Toxicon. 1986;24(4):347-356.

The mothematics of female pheromone signaling: strategies for aging virgins.

I was just doing a quick web search to see if anyone else had used my neologism mothematics, turns out they have, so it’s not my neologism at all. It was used in a couple of places before I adopted it for my moths and butterflies galleries, including in the title of a scientific research paper:

The mothematics of female pheromone signaling: strategies for aging virgins.

The paper was written by Umbers, Symonds, and Kokko of the Centre of Excellence in Biological Interactions at the Australian National University, in Canberra and published in The American Naturalist in 2015. Quite a provocative title, the paper discusses the cost to female moths in pumping out a pheromone plume to attract a mate. Costs to the female might include the energy and resources costs of the biosynthesis of the pheromones themselves. There might also be unwanted attention from olfactory eavesdroppers, such as parasites and predators who follow the pheromone trail to the female. It is also possible that a pheromone plume might attract too many males. The team suggests that for night-time pheromonal moths, earlier in the night might be optimal.

The team also hinted that younger females might have evolved to signal less intensely, pumping out less pheromone for a shorter time. However, older virgin females become less guarded as they age and will spray their sexual attractant at higher concentration and for longer in an attempt to secure their reproductive success before their time is up.

It’s a bug’s life

I briefly review Daniel Marlos’ latest book, Curious World of Bugs, in Six Sexy Science Books. But, I wanted to know more about the book and so offered Marlos a few questions on which he might wax lyrical.

What makes bugs such a fascinating subject?

Bugs make such a fascinating subject because they are ubiquitous. Bugs can be found all over the world in every conceivable environment. Unlike larger animals that flee when they are being observed, bugs couldn’t care less who is watching them and they are ready subjects to be photographed. Many children have a fascination with bugs, though sadly, most adults outgrow this initial reaction to the lower beasts.

What is the most remarkable bug?

This is of course my opinion, but I find the preying mantis to be the most remarkable bug. They are large and formidable predators. There is something almost human in their gestures and they will follow their prey or a larger predator by rotating their heads nearly completely around.

What’s the biggest? And prehistorically how does it compare to those giants of the past?

I would have to question a definition of biggest. The moth with the largest wingspan at twelve inches is the South American white witch. The moth with the greatest surface wing area is the Southeast Asian atlas moth. The longest insect is probably a walkingstick from Borneo that has been recorded at 14 inches long. The insect with the greatest mass is probably the African goliath beetle but the longest beetle is a South American longhorn beetle called a titan beetle that can cover the palm of an adult man, and that doesn’t include its substantial antennae. All of these are dwarfed by a prehistoric dragonfly that has been recorded in the fossil record as having a 30 inch wingspan.

Social insects are, in a sense, meta-organisms aside from our use of bees, do you think we could somehow engineer colonies to carry out other tasks?

Other than honey bees, I don’t think humans would have much luck tapping the social insect world to perform menial labour tasks. Wasps would sting and termites might eat our wooden homes. Ants would compete for food, so it seems we are limited to apiculture when it comes to having social insects perform a service for people.

Bugs will no doubt be here long after we as a species have burned outselves out, might there be a future with “intelligent” bugs?

Depending upon how intelligence is defined, there are numerous intelligent insects. Cockroaches can be taught to run a maze. Social insects like ants, bees, wasps and termites have a highly developed caste system and the individual will sacrifice for the good of the colony. Though social insects care for their young, they are not the only bugs to do so. Many spiders will defend their eggs and hatchlings including the nursery web spiders and the green lynx spider. Many parasitic wasps like the cicada killer, the great golden digger wasp and the tarantula hawk battle and paralyze insects and spiders to provision a nest for their young. Some predatory fireflies mimic the light flashing patterns of more docile species to entrap them for prey, and certain tropical cockroach males are female impersonators that trick more dominant males into mating and while the dominant male is in a compromising position, the female impersonator bites off its competitor’s wings, virtually emasculating him.

Why do you think so many people are so repelled by bugs, despite their obvious merits?

People are often repelled by things they don’t understand, which is one of the reasons humans are often such an intolerant society.

To us Brits, a bug is a germ, a microbe that causes an illness, could that be the subject of The Curious World of Bugs 2.0?

Not a chance. I am not interested in viewing the world through a microscope. Besides, germs are better left to scientists and not artists with an interest in pop culture like me.