Mellittophagous

No later than two weeks ago, I’ve met with a very nice insect. Trichodes apiarius, that’s for a name. I like this beetle, and the latest time I saw one was something like 11 years ago. Quite a long time. Well, I’ve been in & out and it is infeodated to Europe so I’ve lost touch for a good reason at least (although the Genus extend into North America, I didn’t encounter any). Nice to see you again, little beastie!

Just so that you see it, here it is:

Beezarre beetle

Now, I just learn it is quite interesting.

First of all, it belongs to a coleopteran family that’s just quite cool. Cleridae. Or checkered beetles. Indeed. You can check this one: it’s red. Well, it might be yellow as well. Or even something else. This is because the family has a long history of pretending to be otherwise: there are many mimicks among them [1]. They mimick other beetles, wasps, moths (Zygena) and may even try mimicking mimicks. The thing is, this family has members that are so good as mimicks that it mislead some entomologists into thinking that they may belong to different families and not represent an actual group of their own.

Trichodes apiarus was apparently already known in antiquity. These insects are bee predators at the larvae stage (usually they attack solitary bees). Well, they can make a living feeding on pollen early in life, but it’s best to them feeding on bee larvae. Occasionnally larvae produce a cocoon to survive wintertimes. This is were Pierre André Latreille assumes Aristotle was refering to this Genus when writing about cleros, a ‘silk producing worm’ inhabiting hives [2]. That would be amazing, but on the other hands, not so surprising that we know about it given its probable importance as pest to bees.

And the most amazing about the species is that larva apparently have the opportunity to keep their wormy business for several years [3]. They usually take two years before they “decide” to pupate and begin their new life as adults. Interestingly, it is frequent that larvae don’t undergo pupation this early, but may stay several years at this stage (up to 8 when this paper was published [3], and they continue to moult even if there’s no information as to whether growth stops or not). They have a decreasing chance to succeed pupation if they do so too long though. It seems that this feature characterises the Genus (a closely related species does the same, despite a cycle grossly lasting a year most of the time). Larvae are itinerant and travel their ways in between two successive hosts, are able to feed on pollen and can fast for long periods of time (a year long doesn’t result into significant increase in mortality[3]). This is probably a safe way to ensure become adult and reproduce despite enduring bad times, but this is still quite striking. That said, their hosts have evolved a (rather) bad habit of nesting at the same place from one generation to the other, so I guess that good solitary bee habitats are place where evolving a ‘remnant’ larvae strategy doesn’t occur at a such a great cost, since there will probably be enough food to safely achieve the larval cycle…

Trichodes apiarius feeding on pollen

I don’t know whether the word melittophagous really exists or not. And if it does, whether it is dealing with bees or honey. But since our critter today accomodate both, I thought it didn’t involve a great risk of making a mistake. And I like it. Mellittophagous…

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[1] – J.R. Mawdsley (1994). Mimicry in Cleridae (Coleoptera). The Coleopterist Bulletin 48(2): 115-125.

[2] – P.A. Latreille (1831). Cours d’entomologie, ou De l’histoire naturelle des crustacés, des arachnides, des myriapodes et des insectes: à l’usage des élèves de l’école du Muséum d’histoire naturelle. Roret Publisher. (pp. 62 & 63).

[3] – S. Carré (1980). Biologie de deux prédateurs de l’abeille solitaire Megachile rotundata (=pacifica Panz.) [Hymenoptera, Megachilidae]: Trichodes alvearius F. et Trichodes Apiarius L. [Coleoptera, cleridae]: Méthodes de lutte. Apidologie 11: 255-295.

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