Males perceive honest information from female released sex pheromone in a moth

Abstract

There is accumulating evidence that male insects advertise their quality to conspecific females through pheromones. However, most studies of female released sex pheromone assume information transfer regarding merely the species of the female and her mating status. We show that more information is conveyed through the female sex pheromone, positioning it as an honest sexual trait. We demonstrate that females in bad physical conditions (small, starved, or old) lay significantly fewer eggs than females in good conditions (large, fed, or young). The ratio of components in the sex pheromone blend in gland extracts of the female pink bollworm moths provided honest information on most of the phenotypic conditions tested, whereas the pheromone amount in the glands provided an honest signal of quality for extreme phenotypes only. Moreover, males used the information conveyed by the female pheromone to choose their mates, approaching females that signaled higher reproductive potential. In addition, when simulating the female effect, using the synthetic pheromone blend that represents higher quality females (0.6:0.4 ZZ:ZE), more males were attracted to this blend than to the blend representing the population mean (0.5:0.5 ZZ:ZE). Both, female advertisement for males and the male choosiness, suggest that pheromones have evolved as sexual traits under directional, sexual selection. We suggest that the pheromone blend may serve as a multicomponent signal whereby each component adds information concerning the current condition of the female, and all are necessary to elicit a mate searching response.

Gut parasites infection increases mate rejection in a species with indirect sperm transfer

“…In studies of male mate choice (not related to parasitism), males can assess multiple cues such as body size or pheromones to evaluate female condition and make a choice either by accepting a courting female or by courting a specific female over others (Edward & Chapman, 2011). There are some examples of male mate choice in arthropods such as the fiddler crab Austruca mjoebergi , where males choose larger females since body size is positively correlated with clutch size, and in the moth Pectinophora gossypiella , males also prefer pheromones of larger females (Gonzalez‐Karlsson et al, 2021; Reading & Backwell, 2007). In vertebrates as the humpback whale Megaptera novaeangliae , males prefer females with higher reproductive potential, and in the zebra finches Taeniopygia guttata , males choose more fecund females (Craig et al, 2002; Jones et al, 2001).…”

Behavioural consequences of intraspecific variability in a mate recognition signal

“…However, intraspecific variation of the pheromone often occurs, such as between populations [12,13]. Diet can be a cause of pheromone variability [14,15], though more and more studies also find within-population variability correlated with factors such as age/maturity, body size or nutritional state [16][17][18]. Therefore, intraspecific sex pheromone variation, especially on a gradual scale, is likely much more…”

“…We tested male responses towards natural CHC chemotypes using bioassays without and with an alternative choice (experiments providing more than one option can be more sensitive when investigating preferences [48]). As variation in mate recognition signals may correlate with the signaller's quality [16,49], female chemotypes in T. zealandicus might differ in fertility. Thus, we assessed the fitness returns for males paired with females from the three chemotypes.…”

More to legs than meets the eye: Presence and function of pheromone compounds on heliothine moth legs

“…Signals that are involved in interspecies interactions are under natural selection. However, sex pheromones also convey information to individuals of the same species (Allison & Cardé, 2008; De Pasqual et al, 2021; Glover et al, 1991; Gonzalez‐Karlsson et al, 2021; Johansson & Jones, 2007; Karlson & Butenandt, 1959; van Wijk et al, 2017; Zhu et al, 1997; Zweerus et al, 2021). These signals can thus also be under sexual selection.…”