Identification of the Sex Pheromone of Holotrichia Reynaudi

The male attractant pheromone of the scarab beetle Holotrichia reynaudi, an agricultural pest native to southern India, was extracted from abdominal glands of females with hexane and analyzed by gas chromatography– mass spectrometry. Field testing of the candidate chemicals, indole, phenol, and anisole, both alone and as binary mixtures, led us to conclude that anisole was the major component of the sex pheromone. Neither male nor female beetles were attracted to indole or phenol on their own. Similarly, when indole and anisole were combined, the attractiveness of the solution did not increase over that obtained with anisole alone. However, combination of phenol and anisole did alter the attractiveness of anisole, with fewer male beetles attracted to the binary mixture than to anisole on its own. The behavior of female beetles was not altered by any of the chemicals tested. Anisole is also the sex pheromone of H. consanguinea, making this the first known example of two melolonthine scarabs sharing the same pheromone.

A precision apparatus, with solid phase micro-extraction monitoring capability, for incorporation studies of gaseous precursors into insect-derived metabolites

An apparatus is described that facilitates the determination of incorporation levels of isotope labelled, gaseous precursors into volatile insect-derived metabolites. Atmospheres of varying gas compositions can be generated by evacuation of a working chamber followed by admission of the required levels of component gases, using a precision, digitised pressure read-out system. Insects such as fruit-flies are located initially in a small introduction chamber, from which migration can occur downwards into the working chamber. The level of incorporation of labelled precursors is continuously assayed by the Solid Phase Micro Extraction (SPME) technique and GC-MS analyses. Experiments with both Bactrocera species (fruit-flies) and a parasitoid wasp, Megarhyssa nortoni nortoni (Cresson) and oxygen-18 labelled dioxygen illustrate the utility of this system. The isotope effects of oxygen-18 on the carbon-13 NMR spectra of 1,7- dioxaspiro[5,5]undecane are also described.

Cuticular Hydrocarbons of Buffalo Fly, Haematobia exigua, and Chemotaxonomic Differentiation from Horn Fly, H.irritans

We determined the quantity and chemical composition of cuticular hydrocarbons of different strains, sex and age of buffalo flies, Haematobia exigua. The quantity of cuticular hydrocarbons increased from less than 1 µg/fly for newly-emerged flies to over 11 µg/fly in 13 d-old flies. The hydrocarbon chain length varied from C21 to C29, with unbranched alkanes and monounsaturated alkenes the major components. Newly emerged flies produced almost exclusively C27 hydrocarbons. Increasing age was accompanied by the appearance of hydrocarbons with shorter carbon chains and an increase in the proportion of alkenes. 11 Tricosene and 7-tricosene were the most abundant hydrocarbons in mature buffalo flies. Cuticular hydrocarbons of buffalo flies are distinctly different from those of horn flies. The most noticeable differences were in the C23 alkenes, with the major isomers 11- and 7-tricosene in buffalo flies and (Z)-9- and (Z)-5-tricosene in horn flies, respectively. Cuticular hydrocarbon analysis provides a reliable method to differentiate buffalo and horn fly, which are difficult to separate morphologically. The differences in cuticular hydrocarbons also support their recognition as separate species, H. exigua and H. irritans, rather than as subspecies.

(Z)-11-Hexadecenal and (3Z,6Z,9Z)-Tricosatriene: Sex Pheromone Components of the Red Banded Mango Caterpillar Deanolis sublimbalis

The sex pheromone of the red banded mango caterpillar, Deanolis sublimbalis (Lepidoptera: Crambidae), a serious pest of the mango Mangifera indica (Anacardiaceae) in India and Southeast Asia and a recent invader into northern Australia, has been identified. Three candidate compounds were identified from pheromone gland extracts of female moths, using gas chromatography (GC), GC-electroantennographic detection and GC-mass spectrometric analyses, in conjunction with dimethyldisulfide derivatization. Field bioassays established that both (Z)-11-hexadecenal (Z11-16:Ald) and (3Z,6Z,9Z)-tricosatriene (3Z,6Z,9Z-23:Hy) were required for attraction of male D. sublimbalis moths, and 1,000 μg of a 1:1 mix of Z11-16:Ald and 3Z,6Z,9Z-23:Hy was more attractive to male moths than caged virgin females. However, the binary blend was only attractive when the isomeric purity of the monounsaturated aldehyde was >99%, suggesting that the (E)-isomer was inhibitory. Although (Z)-11-hexadecen-1-ol (Z11-16:OH) was tentatively identified in gland extracts, the addition of this compound to the binary blend did not increase the numbers of moths captured. The pheromone can now be used in integrated pest management strategies.

Evolution of sex ratios in social hymenoptera: consequences of finite brood size

Evolutionarily stable sex ratios are determined for social hymenoptera under local mate competition (LMC) and when the brood size is finite. LMC is modelled by the parameter d. Of the reproductive progeny from a single foundress nest, a fraction d disperses (outbreeding), while (1-d) mate amongst themselves (sibmating). When the brood size is finite, d is taken to be the probability of an offspring dispersing, and similarly, r, the proportion of male offspring, the probability of a haploid egg being laid. Under the joint influence of these two stochastic processes, there is a nonzero probability that some females remain unmated in the nest. As a result, the optimal proportion of males (corresponding to the evolutionarily stable strategy, ESS) is higher than that obtained when the brood size is infinite. When the queen controls the sex ration, the ESS becomes more female biased under increased inbreeding (lower d), However, the ESS under worker control shows an unexpected pattern, including an increase in the proportion of males with increased inbreeding. This effect is traced to the complex interaction between inbreeding and local mate competition.

Host recognition by a polyphagous lepidopteran (Helicoverpa armigera): Primary host plants, host produced volatiles and neurosensory stimulation

An important question in the host-finding behaviour of a polyphagous insect is whether the insect recognizes a suite or template of chemicals that are common to many plants? To answer this question, headspace volatiles of a subset of commonly used host plants (pigeon pea, tobacco, cotton and bean) and nonhost plants (lantana and oleander) of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) are screened by gas chromatography (GC) linked to a mated female H. armigera electroantennograph (EAG). In the present study, pigeon pea is postulated to be a primary host plant of the insect, for comparison of the EAG responses across the test plants. EAG responses for pigeon pea volatiles are also compared between females of different physiological status (virgin and mated females) and the sexes. Eight electrophysiologically active compounds in pigeon pea headspace are identified in relatively high concentrations using GC linked to mass spectrometry (GC-MS). These comprised three green leaf volatiles [(2E)-hexenal, (3Z)-hexenylacetate and (3Z)-hexenyl-2-methylbutyrate] and five monoterpenes (α-pinene, β-myrcene, limonene, E-β-ocimene and linalool). Other tested host plants have a smaller subset of these electrophysiologically active compounds and even the nonhost plants contain some of these compounds, all at relatively lower concentrations than pigeon pea. The physiological status or sex of the moths has no effect on the responses for these identified compounds. The present study demonstrates how some host plants can be primary targets for moths that are searching for hosts whereas the other host plants are incidental or secondary targets.

We need to support paedophiles to prevent child sex offending

The sexual abuse of children is, understandably, a key concern for the public. Child sexual abuse can cause long-lasting harms for victims, ranging from relationship difficulties to eating disorders. But misperceptions about those who perpetrate it abound in public debate. Although the terms “paedophile” and “child sex offender” are often used interchangeably, the two are distinct. Paedophiles are sexually attracted to young children. They have either acted on this attraction or fear they might. But not all paedophiles act on their attraction – and this is where support services can help reducing offending. Conversely, not everyone who offends sexually against a child is a paedophile. Some may have a sexual interest in and/or offend against both children and adults. Others do not have a sexual attraction to children but instead act opportunistically...

Resistance to insect growth regulator insecticides in populations of sheep lice as assessed by a moulting disruption assay

Low-volume, backline applications with the benzoylphenyl urea insecticides triflumuron and diflubenzuron represent in excess of 70% of treatments for the control of sheep lice, Bovicola ovis (Schrank) (Phthiraptera: Trichodectidae), in Australia. Reports of reduced effectiveness from 2003 and subsequent controlled treatment trials suggested the emergence of resistance to these compounds in B. ovis populations. A laboratory assay based on the measurement of moulting success in nymphs was developed and used to assess susceptibility to diflubenzuron and triflumuron in louse populations collected from sheep where a control failure had occurred. These tests confirmed the development of resistance to triflumuron and diflubenzuron in at least two instances, with estimated resistance ratios of 67-94X at LC50.

Book Review "Selling sex: a hidden history of prostitution", R. Frances, UNSW Press, Sydney, 2007

In the opening pages of Selling Sex we are introduced to 'Joy', a statue of a young female sex worker which stood in East Sydney for eighteen months during 1995- 1997. Following complaints by local residents, the statue was removed from public view and returned to its owner. Evidently, Joy was considered a reminder of the community's 'bad old days', when it was better known for prostitution than restaurants. In a nation in which almost every sizable community has proudly erected monuments to military men, the removal of Joy reveals much about labour and gender relations in Australia. For Frances, the removal of Joy is symbolic, our historical treatment of sex workers having parallels with our treatment of the convicts. This work sets out to give these women (male prostitutes do not figure in this history) a voice and break with the stereotypes of 'abandoned whores' or 'sad victims'. It also sets out to place the sex industry in the broader national and international context in which it has historically operated...

The host range of Isturgia deeraria, an insect considered for the biological control of Acacia nilotica in Australia

The geometrid caterpillar Isturgia deerraria was imported from Kenya into quarantine facilities in Australia as a potential biological control agent for prickly acacia, Acacia nilotica subsp. indica (Benth.) Brenan (family Mimosaceae). The insect was then tested on 30 plant species presented to neonate larvae as a no-choice cut foliage test and 13 plant species presented as a no-choice potted plant test. In these tests the insect was able to complete its life cycle on 13 native Acacia spp. and also on Acacia farnesiana and the exotic ornamental Delonix regia (family Caesalpiniaceae). The tests supported field observations that the insect has a host range spanning many leguminous species and as such the insect could not be considered for release in Australia.

Interrogating an insect society

Insect societies such as those of ants, bees, and wasps consist of 1 or a small number of fertile queens and a large number of sterile or nearly sterile workers. While the queens engage in laying eggs, workers perform all other tasks such as nest building, acquisition and processing of food, and brood care. How do such societies function in a coordinated and efficient manner? What are the rules that individuals follow? How are these rules made and enforced? These questions are of obvious interest to us as fellow social animals but how do we interrogate an insect society and seek answers to these questions? In this article I will describe my research that was designed to see answers from an insect society to a series of questions of obvious interest to us. I have chosen the Indian paper wasp Ropalidia marginata for this purpose, a species that is abundantly distributed in peninsular India and serves as an excellent model system. An important feature of this species is that queens and workers are morphologically identical and physiologically nearly so. How then does an individual become a queen? How does the queen suppress worker reproduction? How does the queen regulate the nonreproductive activities of the workers? What is the function of aggression shown by different individuals? How and when is the queen's heir decided? I will show how such questions can indeed be investigated and will emphasize the need for a whole range of different techniques of observation and experimentation.

Characterising insect plant host relationships facilitates understanding multiple host use

Weed biocontrol relies on host specificity testing, usually carried out under quarantine conditions to predict the future host range of candidate control agents. The predictive power of host testing can be scrutinised directly with Aconophora compressa, previously released against the weed Lantana camara L. (lantana) because its ecology in its new range (Australia) is known and includes the unanticipated use of several host species. Glasshouse based predictions of field host use from experiments designed a posteriori can therefore be compared against known field host use. Adult survival, reproductive output and egg maturation were quantified. Adult survival did not differ statistically across the four verbenaceous hosts used in Australia. Oviposition was significantly highest on fiddlewood (Citharexylum spinosum L.), followed by lantana, on which oviposition was significantly higher than on two varieties of Duranta erecta (‘‘geisha girl’’ and ‘‘Sheena’s gold’’; all Verbenaceae). Oviposition rates across Duranta varieties were not significantly different from each other but were significantly higher than on the two non-verbenaceous hosts (Jacaranda mimosifolia D. Don: Bignoneaceae (jacaranda) and Myoporum acuminatum R. Br.: Myoporaceae (Myoporum)). Production of adult A. compressa was modelled across the hosts tested. The only major discrepancy between model output and their relative abundance across hosts in the field was that densities on lantana in the field were much lower than predicted by the model. The adults may, therefore, not locate lantana under field conditions and/or adults may find lantana but leave after laying relatively few eggs. Fiddlewood is the only primary host plant of A. compressa in Australia, whereas lantana and the others are used secondarily or incidentally. The distinction between primary, secondary and incidental hosts of a herbivore species helps to predict the intensity and regularity of host use by that herbivore. Populations of the primary host plants of a released biological control agent are most likely to be consistently impacted by the herbivore, whereas secondary and incidental host plant species are unlikely to be impacted consistently. As a consequence, potential biocontrol agents should be released only against hosts to which they have been shown to be primarily adapted.