Abstracts - Samara M. M. Andrade


Samara M. M. Andrade1*, Diogo Montes-Vidal2, Daiane Szczerbowski3, Jeremy D. Allison4 and Paulo H. G. Zarbin5

1 Federal University of Paraná (UFPR), Biology Department - Entomology, Curitiba/PR, Brazil 81531-980; samara.andrade@ufpr.br
2 Federal University of Minas Gerais (UFMG); Chemistry Department, Belo Horizonte/MG, Brazil 31270-901; vidal@qui.ufmg.br
4 Natural Resources Canada, Great Lakes Forestry Centre (NRCan-GLFC), Sault Ste. Marie/ON, Canada P6A 2E5; Jeremy.Allison@NRCan-RNCan.gc.ca
3, 5 Federal University of Paraná (UFPR), Chemistry Department, Curitiba/PR, Brazil 81531-980; pzarbin@ufpr.br
* Correspondence: samara.andrade@ufpr.br

This study evaluates the role of epicuticular compounds of female Hedypathes betulinus mediating mate recognition in this species. From September, 2016-April, 2017, adults of H. betulinus were captured from the field and kept in laboratory for at least 10 days prior to assay. The complete mating sequence of H. betulinus includes the behaviours of: (i) female approaches the male, (ii) male touches the female with the antennae, (iii) mounts and (iv) attempts to copulate. Crude extracts of 30 females were manipulated to produce three fractions: alkanes (A); alkenes (B); and polar compounds (C). Sixty-four females were manipulated to produce three treatments, and presented to 110 males: 1) death by freeze at -20°C; 2) extraction of epicuticular compounds; 3) reconstitution of the crude extract, individual, binary or tertiary blends of fractions. An individual male was sequentially assayed with the same female that was manipulated to produce each of the three treatments. Bioassays were terminated after the female touched the male antennae three times, or once the full mating behavioural sequence was observed (males were always interrupted before copulation occurred). The males` response to females was scored either 1 (behaviour was observed) or 0 (behaviour was not observed). The Fisher Exact Test was used to compare the male copulation response (MCR) to the crude extract, individual and blends of fractions with the MCR to freeze killed females; and to contrast all bioassays with the crude extract and individual fractions. Crude extract treated female cadavers and freeze-killed females had the same MCR rate. There is strong indication that fraction C is necessary and sufficient to recover the MCR to the crude extract. We accomplish that male H. betulinus rely on chemical cues to identify conspecific females, and the chemical compounds present on the epicuticular wax layer of females play an important role mediating mate recognition in this species. In addition, the fractions have specific effects on male H. betulinus copulation rate observed during the fractionation experiments that resulted in various combinations of outcomes.