Sirex woodwasp Sirex noctilio (Hymenoptera: Siricidae): revisiting some past perceptions

The Sirex Woodwasp, Sirex noctilio Fabricius, is the focus of extensive global research because of its pest status, damage potential and ongoing spread within commercial softwood plantations and native forest ecosystems worldwide. In this overview, some small but persistent errors in the reported biological attributes of S. noctilio and its biological control nematode are highlighted. First, an error is noted in the equations reported for estimating size/fecundity relationships, whereby the female S. noctilio prothorax should be measured in cm, not mm. Second, the temperature requirements for egg-adult development time are recalculated to provide more precise estimates of lower thermal threshold (5.1 °C) and cumulative day-degree requirements (1973) using modern software techniques. Third, the origin of the Australian laboratory culture of Amylostereum areolatum used in rearing Deladenus siricidicola is clarified: it was collected from S. noctilio in Mt Gambier, South Australia, around 1995. It is envisaged that these corrections will result in improved research efforts. © 2016 Australian Entomological Societ

Eriophyid mites on spotted gums: population and histological damage studies of an emerging pest

A suite of co-occurring eriophyid mite species are significant pests in subtropical Australia, causing severe discolouration, blistering, necrosis and leaf loss to one of the region's most important hardwood species, Corymbia citriodora subsp. variegata (F. Muell.) K. D. Hill & L. A. S. Johnson (Myrtaceae). In this study, we examined mite population dynamics and leaf damage over a 1-year period in a commercial plantation of C. citriodora subsp. variegata. Our aims were to link the incidence and severity of mite damage, and mite numbers, to leaf physical traits (moisture content and specific leaf weight (SLW)); to identify any seasonal changes in leaf surface occupancy (upper vs. lower lamina); and host tree canopy strata (upper, mid or lower canopy). We compared population trends with site rainfall, temperature and humidity. We also examined physical and anatomical changes in leaf tissue in response to mite infestation to characterize the plants' physiological reaction to feeding, and how this might affect photosynthesis. Our main findings included positive correlations with leaf moisture content and mite numbers and with mite numbers and damage severity. Wet and dry leaf mass and SLW were greater for damaged tissue than undamaged tissue. Mites were distributed equally throughout the canopy and on both leaf surfaces. No relationships with climatic factors were found. Damage symptoms occurred equally and were exactly mirrored on both leaf surfaces. Mite infestation increased the overall epidermal thickness and the number and size of epidermal cells and was also associated with a rapid loss of chloroplasts from mesophyll cells beneath damage sites. The integrity of the stomatal complex was severely compromised in damaged tissues. These histological changes suggest that damage by these mites will negatively impact the photosynthetic efficiency of susceptible plantation species

Effects of mate availability on female longevity, fecundity and egg development of Homichloda barkeri (Jacoby) (Coleoptera : Chrysomelidae)

This study examined the effect of the number of maternal matings on egg production, embryonic development and female longevity in Homichloda barkeri (Jacoby) (Cole optera: Chrysomelidae). Single-mated females lived longer than multiple-mated and unmated females. The number of eggs produced per day and the proportion of eggs that developed between single- and multiple-mated females was not affected by mating frequency

Mites as fungal vectors? The ectoparasitic fungi of mites and their arthropod associates in Queensland

We examined log-inhabiting arthropods and their associated mites for ectoparasitic fungi (Ascomycetes: Laboulbeniales) in South-east Queensland and Far North Queensland. Fungus host records were: Rickia berlesiana (Baccarini) on most species of Fedrizziidae (Acari: Mesostigmata) and three species of Passalidae (Coleoptera); Rickia leptaulacis Thaxter on two species of Fedrizzia (Fedrizziidae), one species of Megisthanus (Mesostigmata: Megisthanidae), and two species of Passalidae; Rickia sp. A on two species of Paradiplogynium (Mesostigmata: Diplogyniidae) and the cockroach Panesthia tryoni Shaw (Blaberidae); Rickia sp. B on two species of Fedrizzia; Rickia sp. C on one species of Megisthanus; Rickia sp. D on Promegistus armstrongi (Mesostigmata: Promegistidae); and Dimorphomyces sp. A on a species of Micromegistus (Mesostigmata: Parantennulidae). Our data are the first records of Dimorphomyces in Australia, R. leptaulacis on mites, and Laboulbeniales on members of the Diplogyniidae, Parantennulidae, and Promegistidae. At a species-level, 15-88 per cent of mites were infested with Laboulbeniales; the most thalli found on a single mite was 34. Thalli of R. berlesiana and R. leptaulacis were especially common on old passalid beetles, but were rare on young beetles. Thalli were common on the ventral prothorax, and leg femora and tibiae, but were mostly found on the mesothoracic episternum and anterior elytra of beetles. Given the protected positions that most thalli occur, and that these positions are the preferred sites for mite associates, we hypothesise that mites are important vectors of fungi between beetles

Consequences of Corymbia (Myrtaceae) hybridisation on leaf-oil profiles

The present study examines patterns of heritability of plant secondary metabolites following hybridisation among three genetically homogeneous taxa of spotted gum (Corymbia henryi (S.T.Blake) K.D.Hill & L.A.S.Johnson, C. citriodora subsp. variegata (F.Muell.) K.D.Hill & L.A.S.Johnson and C. citriodora (Hook.) K.D.Hill & L.A.S.Johnson subsp. citriodora (section Maculatae), and their congener C. torelliana (F.Muell.) K.D.Hill & L.A.S.Johnson (section Torellianae)). Hexane extracts of leaves of all four parent taxa were statistically distinguishable (ANOSIM: global R = 0.976, P = 0.008). Hybridisation patterns varied among the taxa studied, with the hybrid formed with C. citriodora subsp. variegata showing an intermediate extractive profile between its parents, whereas the profiles of the other two hybrids were dominated by that of C. torelliana. These different patterns in plant secondary-metabolite inheritance may have implications for a range of plant-insect interactions

The response of native Australian rodents to predator odours varies seasonally: a by-product of life history variation?

Small mammals are subject to predation from mammalian, avian and reptilian predators. There is an obvious advantage for prey species to detect the presence of predators in their environment, enabling them to make decisions about movement and foraging behaviour based on perceived risk of predation. We examined the effect of faecal odours from marsupial and eutherian predators, and a native reptilian predator, on the behaviour of three endemic Australian rodent species (the fawn-footed melomys, Melomys cervinipes, the bush rat, Rattus fuscipes, and the giant white-tailed rat, Uromys caudimaculatus) in rainforest remnants on the Atherton Tableland, North Queensland, Australia. Infrared camera traps were used to assess visit rates of rodents to odour stations containing faecal and control odours. Rodents avoided odour stations containing predator faeces, but did not avoid herbivore or control odours. The responses of the three prey species differed: in the late wet season U. caudimaculatus avoided predator odours, whereas R. fuscipes and M. cervinipes did not. In contrast, in the late dry season all three species avoided odour stations containing predator odours. We speculate that these different responses may result from variation in life history traits between the species. (c) 2006 The Association for the Study of Animal Behaviour Published by Elsevier Ltd. All rights reserved

Containership routing problem with stochastic travel times, simultaneous deliveries and pick-ups and time deadlines: Τhe case of the Aegean Sea

172 σ.Η ισχυρή επίδραση των καιρικών συνθηκών στη λειτουργία των εμπορικών πλοίων επιδρά σημαντικά στο συνολικό χρόνο εν πλω αλλά και στο ολικό κόστος της μεταφορικής διαδικασίας. Η παρούσα διπλωματική εργασία εστιάζει στο αντικείμενο της δρομολόγησης πλοίων μεταφοράς εμπορευματοκιβωτίων, με στοχαστική όμως θεώρηση των χρόνων διαδρομής, ένεκα της παραπάνω επίδρασης. Αναζητείται, δηλαδή, ο βέλτιστος καθορισμός διαδρομών για έναν ομοιογενή στόλο πλοίων που θα παραλαμβάνει, μεταφέρει και επιδίδει εμπορευματοκιβώτια μεταξύ ενός κεντρικού λιμένα και ενός συνόλου λιμένων που τροφοδοτούνται από αυτόν. Στο πλαίσιο αυτό, μορφώνεται ένα πρόβλημα δρομολόγησης με στοχαστικούς χρόνους διαδρομής, ταυτόχρονη παραλαβή και επίδοση εμπορευμάτων και χρονικούς περιορισμούς, για την επίλυση του οποίου αναπτύσσεται μεθευρετικός αλγόριθμος. Παράλληλα, οργανώνεται η διαδικασία για την εκτίμηση της πιθανοτικής κατανομής των χρόνων διαδρομής του κάθε πλοίου. Το αναπτυσσόμενο πρότυπο εφαρμόζεται σε ένα δίκτυο νησιωτικών λιμένων του Αιγαίου πελάγους. Τα αποτελέσματα από την εφαρμογή καταδεικνύουν ότι ένας μικρού μεγέθους στόλος επαρκεί για την εξυπηρέτηση των αναγκών του δικτύου με μικρές σχετικά καθυστερήσεις, ενώ η διερεύνηση σεναρίων, όπου μεταβάλλονται βασικές παράμετροι του προβλήματος, οδηγούν σε ενθαρρυντικά συμπεράσματα σχετικά με την αποδοτικότητα και την ευρωστία του αλγορίθμου.The strong effect of weather conditions on the operation of commercial vessels has a major influence on the total time at sea and on the total cost of the transport process. This thesis focuses on containership routing, with stochastic consideration of travel times due to the above effect. Ιn this context, aims to determine optimal routes for a homogeneous fleet performing pick-ups, transport and deliveries of containers between a hub and several spoke ports, fed by the hub. The problem is originally formulated as a vehicle routing problem with stochastic travel times with simultaneous pick-ups and deliveries and time constraints and solved using a metaheuristics algorithm. The developed model is implemented to a network of island ports of the Aegean Sea. Results on the application of algorithm reveal that a small fleet is sufficient enough to serve network’s islands, under the influence of minor delays. The investigation of alternative scenarios, characterized by changes in the problem’s parameters, leads to encouraging conclusions in respect of efficiency and robustness of the algorithm.Γρηγόριος Χ. Φούντα

Sexually-Transmitted Disease in a Sub-Tropical Eucalypt Beetle: Infection of the Fittest?

The ecology of sexually-transmitted diseases (STDs) is topical in scientific research, and their demography and epidemiology differ from those of classical pathogens and parasites. Transmission of STDs is generally density-independent, occurs via the "fittest" individuals in a population (or, at least, those that achieve the most matings), and reflects differential mating success. STDs can therefore have a major influence on the evolution of host mating systems. We studied the epidemiology of a recently described STD of a chrysomelid beetle in applied and theoretical contexts, exploring the virulence, intensity and prevalence of infection, and using our results to test ecological predictions. Chrysophtharta cloelia is infected with a sexually-transmitted mite (the STD), Parobia captivus. Infection rate over three beetle generations (7 months) was determined and the STD’s effects on fertility, fecundity, longevity, mating success and overwintering survival was measured. Throughout the season around 40% of beetles were infected, with approximately one quarter of such hosts carrying infective life stages of the STD at any one time. Infection by P. captivus significantly decreased overwintering survival, but did not impact on other fitness parameters measured, including mate acceptance. However, more female beetles were infected than male beetles, while within both sexes larger beetles were more likely to be infected. Our results concur with theoretical predictions that STDs may be selected for low virulence and low detectability, while the observation of female bias in infection supports hypotheses regarding variable mating success and mating skews, which we discuss

Relatedness communicated in lemur scent

Lemurs are the most olfactory-oriented of primates, yet there is still only a basic level of understanding of what their scent marks communicate. We analyzed scent secretions from Milne-Edwards' sifakas (Propithecus edwardsi) collected in their natural habitat of Ranomafana National Park, Madagascar. We sought to test whether the scent mark could signal genetic relatedness in addition to species, sex, season, and individuality. We not only found correlations (r 2 = 0.38, P = 0.017) between the total olfactory fingerprint and genetic relatedness but also between relatedness and specific components of the odor, despite the complex environmental signals from differences in diet and behavior in a natural setting. To the best of our knowledge, this is the first demonstration of an association between genetic relatedness and chemical communication in a wild primate population. Furthermore, we found a variety of compounds that were specific to each sex and each sampling period. This research shows that scent marks could act as a remote signal to avoid inbreeding, optimize mating opportunities, and potentially aid kin selection. © 2013 Springer-Verlag Berlin Heidelberg