Acoustic response to a pheromonal cue in the arctiid moth Pyrrharctia Isabella

ABSTRACT. The acoustic properties of the clicks emitted in response to male courtship pheromone by female Pyrrharctia Isabella (J. E. Smith) (Lepidoptera: Arctiidae) have been investigated. Extracts of male scent organs or synthetic male pheromones can be applied to a glass rod and used to stimulate females to produce these sounds. Power spectra, sound pressure readings, and oscillographic analyses show that the acoustic signals elicited by male extracts or synthetic male pheromones are not distinguishable from those produced in response to disturbance (handling). This is the first reported example of a sound produced by a female moth in a sexual context, and is the first reported example in moths of an acoustic response to a pheromonal stimulus.     

Calling behaviour in arctiid moths: The effects of temperature and wind speed on the rhythmic exposure of the sex attractant gland

Female arctiid moths rhythmically extrude their ovipositors and thereby rhythmically expose their sex pheromone glands while calling. In Utetheisa ornatrix this behaviour results in concentration-modulated or pulsed pheromone release. The ovipositor protrusion frequencies were determined for 15 arctiid species: U. ornatrix, Haploa clymene, H. colona, H. lecontei, Pyrrarctia isabella, Estigmene acrea, Spilosoma congrua, S. virginica, Ecpantheria scribonia, Phragmatobia fuliginosa, Apantesis nais, A. arge, Pareuchaetes insulata, Cycnia tenera, and Euchaetes egle. Moth species that call early in the scotophase extrude their ovipositors at high frequencies (up to 170.9 ± 24.9 extrusions/min at 25°C) while moth species that call late in scotophase extrude their ovipositors at low frequencies (down to 68.3 ± 5.4 extrusions/min at 25°C). In all species tested, the ovipositor extrusion frequencies were shown to be temperature sensitive with a mean Q₁₀ of 2.0 ± 0.1. In one species, U. ornatrix, the ovipositor extrusion frequency varies with wind speed. In still air the ovipositor extrusion frequency is 70.1 ± 8.4 extrusions/min and at a wind speed of 120 cm/s the ovipositor extrusion frequency is 142.1 ± 8.3 extrusions/min. Suggested functions for rhythmic ovipositor extrusion during calling are discussed.     

Isolation of Sphingomonas Strains from Ears of Rice and Other Plants of Family Gramineae

Sphingomonas strains were isolated in high frequency from ears of rice (Oryza sativa), Echinochloa crus-galli, and Setaria viridis. Isolates were identified by the rapid method of cellular fatty acid analysis. Isolated Sphingomonas strains have 2-hydroxymyristate as a sole hydroxy fatty acid, ubiquinone Q-10, and glycosphingolipid. This study demonstrated that sphingomonads are members of a natural flora of microorganisms in ears of rice and taxonomically related plants.     

Ultrasonic signals in the defense and courtship ofEuchaetes egle Drury andE. bolteri Stretch (Lepidoptera: Arctiidae)

Euchaetes egle Drury andE. bolteri Stretch produce ultrasound using paired thoracic tymbal organs in both defensive and sexual contexts. The defensive ultrasound produced in response to tactile stimulation is fully characterized. The sounds are sexually monomorphic and species specific in the number of sound pulses produced during each flexion and relaxation of the tymbal, peak frequency, peak intensity, and duration of the interval between flexion and relaxation. Ultrasonic signals play a role in the courtship of both species. Males produce ultrasound just prior to contact with females, and it is shown to be important to courtship success inE. egle. Ultrasonic courtship communication is mapped on a recently proposed cladogram for the family Arctiidae. The use of ultrasound in courtship has evolved on at least three occasions within the family.     

Acoustic courtship communication inSyntomeida epilais Wlk. (Lepidoptera: Arctiidae,Ctenuchinae)

The polka-dot wasp moth,Syntomedia epilais Wlk. (Lepidoptera, Arctiidae, Ctenuchinae), engages in extensive acoustic signaling during courtship. The signals, which are produced by both sexes, consist of sexually dimorphic trains of ultrasonic clicks. Field and laboratory behavioral experiments demonstrated that (1) sound production from both the male and the female is required for mating success, (2) femaleS. epilais show a higher level of acoustic responsiveness to male acoustic signals than to female signals, and (3) males use the female acoustic signals to locate their potential mates. It is suggested that the existence of the system is made possible by a reduction in bat predation pressure, perhaps the result of extreme distastefulness combined with the distinctive acoustic image that flying ctenuchines present to foraging bats.     

Parental Body Mass as a Determinant of Egg Size and Egg Output in an Arctiid Moth (Utetheisa ornatrix)

Females of the moth Utetheisa ornatrix (family Arctiidae) mate preferentially with larger males. As a consequence, females have larger sons and daughters, which have been shown to be more acceptable in courtship and more fecund, respectively. We demonstrate that mating with larger males results in accelerated oviposition by the female on the day after mating and that females are intrinsically prone to lay larger eggs in the first days after mating. Both these additional size-dependent effects have potential adaptive consequences.     

果蝇求偶行为的影响因素及其分子基础

果蝇Drosophila melanogaster Meigen是进行行为遗传学研究的极好材料。果蝇的雄性求偶行为已经被作为行为遗传学研究的模式。文章简要介绍近年来在遗传和分子水平上对果蝇性信息素和求偶行为的研究进展,尤其是突变体在果蝇行为遗传学研究中的应用。通过对果蝇求偶行为的分析,分别介绍果蝇的性信息素及视觉、听觉、嗅觉和味觉相关基因在果蝇求偶和交配行为过程中的作用。     

A survey of androconial organs in the Riodinidae (Lepidoptera)

A comprehensive survey of the occurrence and morphology of alar, abdominal and appendage androconial organs in the Riodinidae is presented based on light microscopy and scanning electron microscopy. Although historically poorly studied, the group actually possesses among the greatest diversity of androconial organs in the butterflies, including coremata, reported here for the first time outside the Lycaenidae and Nymphalidae, and hindleg hairpencils, reported here for the first time in the true butterflies. Twenty-five percent of riodinid species are reported to have androconial organs. The mode of function of these organs and their role in courtship is discussed where known, based on field observations. A number of taxonomic changes are made at the tribal, generic and species level, predominantly in the Symmachiini, based on the occurrence and structure of androconia.  © 2002 The Linnean Society of London, Zoological Journal of the Linnean Society , 2002, 136 , 171–197.     

Investigation of two new putative pheromone components of the invasive Australian redback spider,Latrodectus hasseltii,with potential applications for control

The Australian redback spider, Latrodectus hasseltii preys on at least 10 endemic species in New Zealand, highlighting a need for control. Male redbacks are attracted to virgin females by an airborne pheromone. The aim of this study was to analyse the response of male redback spiders to two volatile chemicals found on the silk of virgin but not mated females, to determine whether these compounds constitute components of the airborne pheromone. Mature male redback spiders were placed in an olfactometer where they had a choice of two stimuli. We compared their response to paired combinations of a control, virgin silk, butyric acid and isovaleric acid. Male redbacks responded equally strongly to butyric acid and virgin silk, in terms of time spent near the stimulus. The identification of butyric acid as a component of the airborne sex pheromone of L. hasseltii provides the groundwork for developing a pheromone-based control.     

The role of heliothine hairpencil compounds in female Heliothis virescens (Lepidoptera: Noctuidae) behavior and mate acceptance

Studies on numerous insect species suggest that male-produced sex pheromones play a role in attracting females; as aphrodisiacs, making females more quiescent; or as a means of inhibiting competing males. Male heliothine moths display abdominal hairpencils during courtship, but the specific effects of the odors released on female behavior have not yet been elucidated. This study investigates the role of male hairpencil compounds in female Heliothis virescens mating behavior. Female H. virescens were exposed to filter paper loaded with hairpencil extracts of male H. virescens, Heliothis subflexa and Helicoverpa zea, and observed for behavioral responses to odors. Single synthetic compounds found in the H. virescens hairpencil blend were also tested. In mating assays between single male and female H. virescens it was found that: (i) antennectomized females mated less frequently than sham-operated females; (ii) females mated less frequently with males whose hairpencils had been surgically removed; (iii) females mated with males with ablated hairpencils if a filter paper loaded with one male equivalent of H. virescens hairpencil extract was presented simultaneously; and (iv) this effect was species-specific, as presentation of H. subflexa or H. zea hairpencil extracts did not restore mate acceptance. This study suggests that odors released by male hairpencils are important in mate acceptance by female H. virescens, and may play a role in mate choice and species isolation.     

Are you Paying Attention? Female Wolf Spiders Increase Dragline Silk Advertisements When Males do not Court

Females of many spider species invest in chemical advertisements to attract males, yet variation in investment relative to the presence or quality of males remains poorly understood. Males of the wolf spider Pardosa milvina court females longer and more intensively when in contact with female silk and also court more intensively when encountering silk from virgin rather than mated females; therefore, females may use silk as a medium to advertise their receptivity to mate. We estimated female investment in advertisements by measuring variation in the quantity and type of silk deposited by females in the presence or absence of males and among males that varied in their courtship intensity. We measured dragline silk, cord silk, and attachment disk deposition from females on gridded sheets of paper in response to four stimuli over a 30‐min period (n = 39/treatment): (1) an intensively (high) courting male with access to female silk, (2) a weakly courting or non‐courting male (low) without access to female silk, (3) no male present, but female silk present (silk control), and (4) no stimulus present (control). Females produced significantly more dragline silk and significantly less cord silk in the presence of low‐courting males compared to any other treatment, but we found no difference in attachment disk deposition across treatments. Our results suggest that females invest more heavily in dragline deposition when encountering low‐courting males. Additional studies are necessary to determine the relative role of different silk types in male–female sexual communication.     

The biology of Creatonotos (Lepidoptera: Arctiidae) with special reference to the androconial system

The reproductive biology of the arctiid moths Creatonotos transiens and C. gangis exhibits a novel ontogenetic phenomenon, the morphogenesis of male coremata size being directly controlled by the quantity of hostplant-derived pyrrolizidine alkaloids ingested by the larvae. In addition, the same alkaloids directly control the quantity of male pheromones synthesized and available for deployment by these scent organs. Reproduction in these insects thus shows striking linkages between ecological, behavioural, chemical and morphological features. This paper presents an account of the general biology of the moths, and reviews the literature on Creatonotos as a basis for reports on experimental work.