Ready for another science post? The laws of physics deemed that today there would be two.
A new paper in the Journal of Orthoptera Research by Sigfrid Ingrisch et al. (free link if you join Researchgate [also free]; reference below) describes two recently-discovered and newly-described katydids from Sabah (part of Malaysia on the northern part of Borneo). I’m busy today and can’t write about this at length (and, in truth, you don’t need to know more than what I’m putting down here), but have a look at the abstract, which notes the vein-like structures that curve backwards on the “tegmen” (forewing), making them resemble the veins of leaves. In one species the females are reddish-pink, like young leaves, while males are green—a remarkable case of sexual dimorphism. (The males of the other species haven’t been found yet.) These are clearly leaf mimics, though there’s an issue with coloration (see below). Here’s the paper’s abstract, which I’ve tried to clarify a bit by defining technical terms):
Two new species of the previously monotypic genus Eulophophyllum Hebard, 1922 are described. All species of the genus known up until now occur in forested areas in Sabah, Borneo. The genus is unique for the strongly widened media field of the tegmen [JAC: hardened forewing], in which all branches of the media anterior plus radius sector are strongly curved and run anteriorally. There is also a striking color difference between the sexes, with males uniformly green and females pink. The two new species E. lobulatum Ingrisch & Riede sp. n. and E. kirki Ingrisch & Riede sp. n. have large leaf-like expansions of the hind tibiae that are absent in E. thaumasium Hebard, 1922. They differ from each other in the number of main vein branches in the media field of the tegmen. Stridulation [JAC: “chirps”, as in crickets, made by rubbing the wings together; the species have a special “file” on one wing that produces the sound] of E. lobulatum sp. n. consists of short double-clicks ranging from 6.5 to 8.5 kHz, repeated at longer intervals.
Here’s a pinned specimen in which you can see the stridulatory “file” apparatus (“D”) and the leaflike expansion of the upper part (tibia) of the hind legs, making them look even more cryptic:
Possible reasons for the pink coloration of the females are as follows: (1) Against a background of variable vegetation a pink female with green veins might merge optically with the background when seen from a distance (Fig. 3G); (2) It is possible that the pink individuals which have so far been found may have simply been resting on an atypical background – making them more obvious to human observers. Their ‘usual’ resting site may be reddish ﬁrst-ﬂush leaves, common in many rainforest plants; (3) the pink coloration might serve as warning coloration, although we consider this to be unlikely. Further ﬁeld observations will be necessary to shed light on the function of the pink coloration of these species and it may reveal something unexpected.
Ingrisch, S., K. Riede, and G. Beccaloni. 2016 The pink katydids of Sabah (Orthoptera: Tettigoniidae: Phaneropterinae: Eulophophyllum with Description of two new species. Journal of Orthoptera Research25:67-74.