TL Johnson, MRE Symonds, MA Elgar (2017a) Sexual selection on receptor organ traits: younger females attract males with longer antennae. The Science of Nature 104: 44 PDF
What’s it about?
Do females moths choose their males by releasing small amounts of pheromone? Does this select for more sensitive males. We tested this through some simple field manipulations with the gum-leaf skeletonizer moth Uraba lugens. First we compared what kind of males turn up at traps baited with two vs. one female (the former representing double the pheromone amount, presumably). While this didn’t affect the number of males turning up, it DID affect the type of male. The males attracted to the single females had longer (more sensitive) antennae. Furthermore, age was relevant. Older females attract fewer males, but also the youngest females attract males with longer antennae, perhaps because they modulate their pheromone production to be choosier (as predicted by Umbers et al. 2015).
What’s the story behind it?
Tamara Johnson has been doing her PhD with Mark Elgar and I for a little while now, having morphed out of an honours project on the evolution of elaborate antennae in a different moth species, Teia anartoides. Some of the questions from that honours project turned out to be more amenably tested using Uraba lugens (read: you can actually find the buggers). My recollection is that the idea for this paper/chapter from Tamara’s thesis, came initially from Mark. He was the one who proposed the simple one or two female trapping experiment as a way of examining whether there was a link between how much pheromone the females put out and the size of the antennae. But Tamara actually had to do the experiment which involved many thankless travels out into Royal Park in Melbourne to find moths. In the end the story was more interesting than that (as is evidenced by the subsequent rather cute media attention the story got). Incidentally, the paper had a rather bizarre handling experience at The Science of Nature (formerly known as the rather austere-sounding Naturwissenschaften) – in short we got 4 reviews, all pretty positive. We revised the paper, but failed to do one minor (we thought) revision to the satisfaction of one reviewer (who hadn’t been particularly clear about what they expected us to do) and the editor rejected the paper outright. We sent a bit of a ‘wtf’ to the editor, who fortunately then turned around and accepted the paper. My feeling is that the editor made a bit of a 3am in the morning Caesar/Mr Dog decision and realised his mistake.
For a more popular science write-up of Tamara’s work where we argue that females prefer sex with good listeners click here
BUT, if you want really a rather wonderful version of this research, with amazing graphics – click here. You won’t regret it – it’s fab (quite the nicest write-up/publicising of research I’ve been involved with).