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Mate choice by males has been recognized at least since Darwin's time, but its phylogenetic distribution and effect on the evolution of female phenotypes remain poorly known. Moreover, the relative importance of factors thought to underlie the evolution of male mate choice (especially parental investment and mate quality variance) is still unresolved. Here I synthesize the empirical evidence and theory pertaining to the evolution of male mate choice and sex role reversal in insects, and examine the potential for male mating preferences to generate sexual selection on female phenotypes. Although male mate choice has received relatively little empirical study, the available evidence suggests that it is widespread among insects (and other animals). In addition to 'precopulatory' male mate choice, some insects exhibit 'cryptic' male mate choice, varying the amount of resources allocated to mating on the basis of female mate quality. As predicted by theory, the most commonly observed male mating preferences are those that tend to maximize a male's expected fertilization success from each mating. Such preferences tend to favour female phenotypes associated with high fecundity or reduced sperm competition intensity. Among insect species there is wide variation in mechanisms used by males to assess female mate quality, some of which (e.g. probing, antennating or repeatedly mounting the female) may be difficult to distinguish from copulatory courtship. According to theory, selection for male choosiness is an increasing function of mate quality variance and those reproductive costs that reduce, with each mating, the number of subsequent matings that a male can perform ('mating investment') Conversely, choosiness is constrained by the costs of mate search and assessment, in combination with the accuracy of assessment of potential mates and of the distribution of mate qualities. Stronger selection for male choosiness may also be expected in systems where female fitness increases with each copulation than in systems where female fitness peaks at a small number of matings. This theoretical framework is consistent with most of the empirical evidence. Furthermore, a variety of observed male mating preferences have the potential to exert sexual selection on female phenotypes. However, because male insects typically choose females based on phenotypic indicators of fecundity such as body size, and these are usually amenable to direct visual or tactile assessment, male mate choice often tends to reinforce stronger vectors of fecundity or viability selection, and seldom results in the evolution of female display traits. Research on orthopterans has shown that complete sex role reversal (i.e. males choosy, females competitive) can occur when male parental investment limits female fecundity and reduces the potential rate of reproduction of males sufficiently to produce a female-biased operational sex ratio. By contrast, many systems exhibiting partial sex role reversal (i.e. males choosy and competitive) are not associated with elevated levels of male parental investment, reduced male reproductive rates, or reduced male bias in the operational sex ratio. Instead, large female mate quality variance resulting from factors such as strong last-male sperm precedence or large variance in female fecundity may select for both male choosiness and competitiveness in such systems. Thus, partial and complete sex role reversal do not merely represent different points along a continuum of increasing male parental investment, but may evolve via different evolutionary pathways.

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The evolution of male mate choice in insects: a synthesis of ideas and evidence.

The idea of using species-specific behavior-modifying chemicals for the management of noxious insects in agriculture, horticulture, forestry, stored products, and for insect vectors of diseases has been a driving ambition through five decades of pheromone research. Hundreds of pheromones and other semiochemicals have been discovered that are used to monitor the presence and abundance of insects and to protect plants and animals against insects. The estimated annual production of lures for monitoring and mass trapping is on the order of tens of millions, covering at least 10 million hectares. Insect populations are controlled by air permeation and attract-and-kill techniques on at least 1 million hectares. Here, we review the most important and widespread practical applications. Pheromones are increasingly efficient at low population densities, they do not adversely affect natural enemies, and they can, therefore, bring about a long-term reduction in insect populations that cannot be accomplished with conventional insecticides. A changing climate with higher growing season temperatures and altered rainfall patterns makes control of native and invasive insects an increasingly urgent challenge. Intensified insecticide use will not provide a solution, but pheromones and other semiochemicals instead can be implemented for sustainable area-wide management and will thus improve food security for a growing population. Given the scale of the challenges we face to mitigate the impacts of climate change, the time is right to intensify goal-oriented interdisciplinary research on semiochemicals, involving chemists, entomologists, and plant protection experts, in order to provide the urgently needed, and cost-effective technical solutions for sustainable insect management worldwide.

Sex pheromones and their impact on pest management.

Odor plumes and how insects use them , Odor plumes and how insects use them , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

/pdf/odor-plumes-and-how-insects-use-them-2g6rjpacf2.pdf

Odor plumes and how insects use them

Male moths generally find their mates by following the females' pheromone plume to its source. A formulated copy of this message is used to regulate mating of many important pests, including the pink bollworm (Pectinophora gossypiella), the oriental fruit moth (Grapholita molesta), and the tomato pinworm (Keiferia lycopersicella). How synthetic disruptant interrupts normal orientation is uncertain, but the most probable mechanisms invoke adaptation and habituation, competition between point sources of formulation and females, and a camouflage of a female's pheromone plume by the formulation. The efficacy of this technology is related principally to the motility of mated females into the area to be managed, the initial population levels of the pest, and the release characteristics of the formulation. In most cases, implementation of this technology necessitates a sophisticated monitoring and management program. Area-wide management schemes are ideal vehicles for using disruptants. Future acceptance of this...

CONTROL OF MOTH PESTS BY MATING DISRUPTION: Successes and Constraints

A simple artificial medium has been developed and handling procedures have been devised to facilitate the mass-rearing of a variety of noctuid species with a minimum expenditure of time and money. The medium, composed of dry beans, yeast, ascorbic acid, agar, water, and 3 mold inhibitors, satisfactorily supports the development of larvae of the cabbage looper, Trichoplusia ni (Hubner) ; the alfalfa looper, Autographa californica (Speyer); the yellow-striped armyworm, Prodenia ornithogalli Guenee; the beet armyworm, Spodoptera exigua (Hubner) ; the bollworm, Heliothis zea (Bocklie) ; the tobacco budworm, H. virescens (F.); H. phloxiphaga G. & R.; the armyworm, Pseudaletia unipuncta (Haworth); and the variegated cutworm, Peridroma saucia (Hubner). Details are given concerning the development, viability, and fecundity of laboratory-reaied individuals of the first 6 of these species.

Mass-Rearing of the Larvae of Nine Noctuid Species on a Simple Artificial Medium

Behavioral Responses to Insect Pheromones

Animal Communication by Pheromones

Propylure, 10-n-propyl-trans-5,9-tridecadienyl acetate, and deet, N,N,-diethyl-m-tolumide, were previously reported as the sex pheromone and a sex pheromone activator, respectively, of the pink bollworm. Neither chemical in three extracts of female moth abdomen tips could be detected by gas-liquid chromatographic analysis. These compounds, alone or in combination, exhibited little or no biological activity in the laboratory or in the field. Hexalure, cis-7-hexadecenyl acetate, a synthetic attractant for pink bollworm males, could not be detected in female moth abdomen tip extracts. The pink bollworm sex pheromone was identified as a mixture of cis,cis and cis,trans isomers of 7,11-hexadecadienyl acetate.

https://science.sciencemag.org/content/sci/181/4102/873.full.pdf

Clarification of the chemical status of the pink bollworm sex pheromone.

The wing vibrations of courting male Drosophila melanogaster Meigen produced pulsations of sound, with each pulse apparently caused by 1 to 2 cycles of wing movement. The average repetition rate at 25 degrees C was 29.8 pulses per second. The rate was dependent on temperature, increasing at 1.4 pulses per additional degree Celsius.

Harry H. Shorey

Papers

Mass-Rearing of the Larvae of Nine Noctuid Species on a Simple Artificial Medium

Behavioral Responses to Insect Pheromones

Animal Communication by Pheromones

Clarification of the chemical status of the pink bollworm sex pheromone.

Nature of the Sound Produced by Drosophila melanogaster during Courtship