Tag Archives: parasitic

Melittobia staking out a mason bee house

I recently set up a mason bee house, and almost instantly attracted a parasitoid, a female Melittobia. She was so tiny that I first thought it was a thrips. But its behavior was odd and definitely not thripsy. The insect would linger near the holes that were being used by mason bees (Chelostoma philadelphi and Osmia sp.), approach, then scurry away, then repeat. On one occasion it peered down an unoccupied hole and paused for several seconds before walking away. It was covered in wood shavings, too, so I inferred that she’d been inside the holes on at least one occasion. All this activity screamed, “parasitoid”, of course, so I had to get some pictures: 

Female Melittobia sp. at a mason bee house.Female Melittobia sp. at a mason bee house.Female Melittobia sp. at a mason bee house. I’m not sure which species she is (there are 14 according to González et al. 2004), but I gather that all members of the genus can parasitize mason bees. Females spend up to 48 hours lurking around a hole (“assessing” per González article) and then puncture a developing larvae with her ovipositor, drink some of the hemolymph, and deposit eggs. There’s a pause in between the hemolymph-feeding and the egg-laying, presumably to allow some of the nutrients to be allocated to eggs. Females are not at all picky about host larvae. Recorded hosts for M. acasta include honeybees, bumblebees, leafcutting bees, and various wasps, flies, beetles, and butterflies (González et al. 2004).

Things get exciting when the wasps eclose, with the early-emerging male killing the slackers that are still developing. There are two types of females: brachytperous (reduced wings) and macroptyrous (regular wing size). I’m assuming the one(s) I viewed are the regular kind.

I’ll post more photographs if I can get them, but whatever is going on inside the holes is of course hidden. But I’m going to make a few glass-sided mason bee houses in the next few weeks so hopefully I can get some larval pics one of these years. This spotting is a reminder to use paper tube inserts whenever possible so that larvae can be examined at the end of the season for parasites. I’m rather interested in parasites but I’d like to encourage a healthy mason bee population when possible.

Much thanks to Ross Hill for identification, and of course to people behind BugGuide for facilitating such IDs. These observations are also logged into iNaturalist.

Planthopper parasite moth larvae

Here are some photographs of Fulgoraecia exigua, a moth that parasitizes planthoppers during its larval phase. There were dozens of these caterpillars at this location, many of them hanging by silk threads. They look like miniature sheep (a parasite in sheep’s clothing, I guess), and are rather cute, I think. But not for planthoppers, as you can probably guess. When the larvae hatch (earlier in the season) they crawl around and seek out planthoppers to latch onto, then suck their juices and eventually displace their hosts’ wings as the weeks go by. I.e., the planthoppers go about their lives with a caterpillar attached to their abdomens. When it’s done feeding the caterpillar lowers itself to the ground on a silk thread and pupates. I’m going to go back to the spot see if I can get photographs of the pupal form, which looks like a miniature version of the Sidney Opera House, built from the waxy fluff that protected them.

Colin Purrington Photography: Insects &emdash; Planthopper parasite moth (Fulgoraecia exigua)

Colin Purrington Photography: Insects &emdash; Planthopper parasite moth (Fulgoraecia exigua)

Colin Purrington Photography: Insects &emdash; Planthopper parasite moth (Fulgoraecia exigua)

Photographed on the Goshen Running Path, Newtown Square, Pennsylvania. Many thanks to Drs Roger Latham and Doug Tallamy for identification help.