Ask an Entomologist

It’s the start of field season, so Joanie, myself, and Nancy all have had a lot to plan for this month.

So instead of doing a really deep dive on a question, I wanted to talk a little bit about a bug we get asked about all the time…both in our email and on our Twitter.

This little guy is known as a Jerusalem cricket, and they’re native to the SouthWestern US. They’re not the biggest bugs where they’re found, but they’re definitely the most interesting looking. Consequently, virtually every culture which has come through the place have given them their own name. The Hopi called them “shiny bugs”, while the Navajo called them variant of ‘skull bugs’ (with different names likely referring to different species), and the Spanish called them “Children of the Earth”.

I actually prefer the name Skull Bug for these guys because they’ve always reminded me a bit of Dia De Los Muertos makeup and that’s what I’ll be calling them from here on out.

Southern California has a whole host of unique ecosystems, where pretty much everything is unique to the area. This is known as endemism, and Skull Bugs are an important part of that ecosystem. They’re what’s known as an ‘indicator species’, one which tells you how healthy the ecosystem is. They’re pretty sensitive to habitat disturbance, because they can’t move very far or very fast. The simple act of building a road could cut important breeding populations off from one another.

Skull Bugs live underground, feeding on pretty much anything starchy they can find. They’re also happy to eat other insects, if the opportunity arises. They can damage potatoes, but they’re not crop pests. Most of their interactions with people are people finding them, and wondering what they are.

These guys are solitary and feircly territorial. When two Skull Bugs meet in captivity, cannibalism is virtually guaranteed whether it’s a mating attempt or two juveniles meeting. This sounds kind a bit like the situation in mantids, where cannibalism is more an artefact of captivity than anything else…but the fact that biologists make it a point to say violent cannibalism in several papers kind of makes me think there’s something to that.

It’s pretty obvious why these guys catch everyone’s eyes. They’re just…cool bugs, and there’s a lot to love about them.

Works Cited

Sánchez-Xolalpa, D. A., Álvarez, H. A., De la Torre-Anzúres, J., & Jiménez-García, D. (2017). Morphometry, Behavior, and Ecology of the Jerusalem Cricket, Stenopelmatus talpa. Southwestern Entomologist, 42(3), 745-752.

We get a lot of weird questions in our inbox about parasites. Most of them, we can’t answer because doing so would amount to giving medical advice…but every so often we get a question completely out of left field. Like this one:

Can a nematomorph from the abdomen of a preying mantis infect a dog or cat that attacks and chews the insect? My cat keeps killing mantises on my deck; it’s mortifying because I love them. A lot of them seem to be infected with nematomorphs. Could it get into my cats digestive system and do harm?

When it comes to doctors and invertebrates, I’m notoriously skeptical because there’s a long history of doctors misdiagnosing brown recuse bites. Rick Vetter-one of my personal heroes-made a long career out of simply pointing out that diagnosis of brown recluse bites do not correlate with the known range of the critters…a series of mistakes which likely masked the rise of community acquired antibiotic resistant flesh-eating bacteria.

It’s not often that I hear a new medical claim, so this was absolutely something I wanted to check out.

Written by Joe Ballenger

I wanted to know if it is possible for the adult butterfly to be poisonous while the caterpillar of the same species is not poisonous?

I think this is a really insightful question, and I’ve got a soft spot for questions asked by kids.

I guess we should start by talking about why this question is really insightful.

Lepidopterans-butterflies and moths-have a huge chemical arsenal at their disposal which ranges from compounds which smell really bad, to venom that’s strong enough to kill humans. There’s a variety of ways they can introduce these compounds, but for the most part, they’re either stored in the body as larvae or they’re based on a developmental program that’s also part of the larva.

So it’s kind of an unusual situation where an adult would be toxic while a larva wouldn’t…but it does exist.

Kind of.

It’s complicated.

Our question this week comes from the Nature Check discord. Nature Check is a project where we use games like D&D to talk about science, and you should totally check it out!

In the food channel, we were talking about bugs as food and the concept of cross-allergies came up. When introducing any new food into the supply chain, it’s something we have to consider because choosing the wrong food could cause a lot of people to get sick.

I’ve discussed the idea of cross-allergies in relation to wasp stings, and they all kind of work the same way. Basically, there’s something you become allergic to. Sometimes, it’s a protein and sometimes it’s a sugar or something like that. If that something is similar enough between different the different kinds of plants and animals you eat as food, you could become allergic to another kind of food.

Given how important food is to my life-I’m an agricultural scientist, after all-I like to keep up on food allergies. I hadn’t heard anything about the cricket/nut allergy connection, and wasn’t able to find any literature about it. That’s not to say that it’s never happened, but I was unable to find any evidence that was a thing.

So, it’s unlikely that kind of cross-reactivity actually exists…but there is a lot of cross-reactivity between different arthropods used as food. These are called pan-allergens because if you become allergic to one critter, suddenly you’re allergic to lots of critters.

So let’s talk about the proteins which make you allergic to everything, and why they can do that.

Written by Joe Ballenger

So this is a fantastic question, especially if you’re trying to shed those extra pounds after Thanksgiving and Christmas.

So do bugs get fat?

Yeah, they do. Sometimes it’s adorable, and sometimes it’s…not.