Production of [14C]-Labeled 3-Hydroxy-L-Kynurenine in a Butterfly,Heliconius charitonia L. (Heliconidae), and Precursor Studies in Butterfly Wing Ommatins

A method was developed to produce radiolabeled 3-hydroxy-L-kynurenine by injection of [¹⁴C]-L-tryptophan into pupae of the heliconid butterfly, Heliconius charitonia, which was converted into [¹⁴C]-3-hydroxy-L-kynurenine and deposited as a wing pigment. Extractions of 3-hydroxykynurenine (3-OHK) with 60% methanol from wings yielded in 14.4 μg per mg dry weight. In extracts from yellow wing areas, 3-OHK represented 100% of detectable amino acids. Resulting specific radioactivity of [¹⁴C]-3-OHK was between 0.05 and 0.07 mCi/mmol when 0.5 μCi [¹⁴C]-tryptophan was injected into pupae 1 or 2 days before emergence of the butterfly. Incorporation of [¹⁴C]-3-OHK into wing ommochromes was studied in nymphalid butterflies, Araschnia levana and Precis coenia. After injection into pupae [^I4C]-3-OHK as well as [¹⁴C]-tryptophan were specifically incorporated into red and red-brown wing scales as shown by autoradiography. The same incorporation occurred in isolated wings after incubation in Grace's medium containing [¹⁴C]-3-OHK. In Araschnia levana, [¹⁴C]-3-OHK offered to left wing pairs was incorporated into dihydroxanthommatin six times more effectively than [¹⁴C]-tryptophan offered to right wing pairs from the same specimen. Therefore, 3-OHK seems to be the ultimate precursor of wing ommatins.     

Note on the glide of a bird with wings bent downwards

This note considers the influence of the bending down of the wings of a bird on the performance of its glide. The induced drag of bent wings is compared with the induced drag of a corresponding straight wing. Numerical results are given.     

The autonomous inflation of insect wings

At adult eclosion, the wings of the locust are expanded by blood pressure. The source of the pressure appears to be from within the wing since a wing cut from the locust will expand as quickly and completely as normal. It seems likely that the pressure is generated by the very quick stiffening of the expanded wing membrane. This phenomenon is not unique to the locust.     

Central projections of the sensory hairs on the gemma of the ant Diacamma: substrate for behavioural modulation?

In the ant genus Diacamma, all workers eclose from their cocoons with little clublike thoracic appendages, called gemmae. Whether these gemmae are mutilated determines individual behaviour, and ultimately reproductive role, in two of the three species examined. The gemmae are covered with sensory hairs, which probably serve a mechanoreceptive function. The sensory afferents arising from these hairs were stained and traced into the central nervous system (CNS). They feature widely distributed collaterals invading all three thoracic ganglia as well as the suboesophageal and the second abdominal ganglia. The multisegmental arborization pattern of the gemma afferents is very similar to that of wing-hair afferents of other ants (queens and males) or other insects in general. This implies that gemmae and wings are homologous structures. We discuss the morphology of the gemma afferents with respect to their possible involvement in the behavioural changes associated with mutilation. The neuronal processing may be modulated by (1) the decrease of sensory input onto interneurons (suggested by the afferents' extensive arborizations); or (2) by the effect of neuromodulatory substances (suggested by the finding that terminals occur within the cell body rind of the ganglion).     

The New Zealand scorpionfly (Nannochorista philpotti comb.n.): wing morphology and its phylogenetic significance1

The win structure of the New Zealand nannochoristid currently known as Microchorista philgotti: (Tillyard, 1917) is described and discussed. Tubular wing vein sclerotizations are developed in the uper win cuticle only. Shortening of the hindwing CuP-A anastomosis to a single point cannot ge uphed as a nannochoristid autapomorphy. Absence of the Rs₃-Rs₄ crossvein (the diagnostic character for Microchorista) and, perhaps, presence of specialized microtrichia patches on the fore wing are autapomorphic of the New Zealand species. Since the genus Nannochorista, comprising the Australian/Tasmanian and S. American nannochoristids, according to available evidence is paraphyletic in terms of Microchorista the latter is synonymized with the former.