Evolutionary trends in the male pheromone systems of arctiid moths: evidence from studies of courtship in Phragmatobia fuliginosa and Pyrrharctia isabella (Lepidoptera: Arctiidae)

Abstract

Male Phragmaiobin, fuI<qinosa and Pvrharciia isabella evert tubular abdominal scent-organs (coreniata during courtship. I'he coremata secrete a pheromone that is derived from pyrrolizidinc alkaloids (PAS) obtained during larval feeding. Field-collected males vary widely in the amount of phrromone they possess. 'l'he courtship behaviour of these species was studied to determine whethrr this variation among males serves as a basis for mate choice by females. In a wind-tunnel a malc approarhes a pheromone-rclcasing female from downwind with his coremata everted in flight. .4 female perceiving the pheromone responds by fluttering her wings and emitting ;i clirking sound. This response did not occur in all courtships, and successful copulation was not dependent on its occurrence. Xlales denied access as larvae to the PA-precursors of the corematal pheromonr i P.4denied males 1 mated as rapidly as males allowed access to pheromone precursor (PA-supplied males). hloreo\ er. antennectomized females mated as rapidly as normal females. Cornparati\ e analyses of transitional probabilities indicated no differences among courtships involving i,I ~ PA-denied males and normal females, (11) PA-supplied males and normal femalcs. or antenncctomized females and normal males of unspecified fcrding histor). Field observations of courtship interartions hrtucen laboratory-reared females and wild males indicated that males having little oi-110 pheromone sucreed in mating in a natural setting as do males having a relativcl! large aniount of phcromonr. I t is hypothesizrd that the failure of female Ph.Julzgino~a and cr. isahella to cnforrc thc display of PA-derived pheromone is rclated to an cvolutionary trcnd away from an ancesti-al lar\ ' 1 1 host-range rrsti-irted to PA-containing plants toward the pohphagy shown b) niany temperate and arctic arrtiids in the lineage (subfamily Arctiinar: tribe Arctiini) to \\liich Ph.h.Julzgi?iom and PY. i~ahella belong. Parallels in other moth groups are cited to suppoi-t the notion that a plrsiomorphic courtship pheromone system could persist in a vestigial statr. drspitr the loss of its adaptive ~n i m n d.?fw.

Effectiveness of tiger moth (Lepidoptera, Arctiidae) chemical defenses against an insectivorous bat (Eptesicus fuscus)

“…It should be noted however that our methods did not allow P. isabella to sample multiple hostplants as they do in nature. Generalist feeding is thought to be associated with the spread of Arctiini out of the tropics into more northern climes (Krasnoff & Roelofs 1990). This spread is accompanied by a decrease in overall exposure to bat predation (Morrill & Fullard 1992;Lewis et al 1993) and perhaps by an overall increase in palatability.…”

The Science of Rijāl as a Method in the Study of Hadiths

“…There are several possible scenarios. The lek-based strategy may be an evolutionary legacy dating from a time when E. acrea was a specialist feeding only on PA-containing plants ( Krasnoff and Roelofs 1990 ). There is evidence that some polyphagous arctiine arctiids evolved from specialist feeders ( Weller et al 1999 ).…”

Sexual Behavior of the Sugarcane Hairy Borer, Hyponeuma taltula (Lepidoptera: Erebidae): Evidence for a Female-Released Sex Pheromone

“…: Crambidae) (Farrell & Andow 2017) and Choristoneura rosaceana (Harris, 1841) (Lep. : Tortricidae) (Curkovic et al 2006), and the rotation of 180 degrees is characteristic of noctuids (Birch et al 1989;Frerot et al 2006;Krasnoff & Roelofs 1990;Nagayama et al 2004). On the other hand, the female responds to copulation with flapping wings and remaining in the same place, a behavior also observed in H. subflexa (Cibrian-Tovar & Mitchell 1991).…”