ABSTRACT
Camouflage and warning signals are different antipredator strategies, which offer an excellent opportunity to study the evolutionary forces acting on prey appearance. Edible prey often escape detection via camouflage, which usually leads to apostatic selection favoring rare morphs. By contrast, defended prey often display conspicuous coloration acting as warning signals to predators, which usually leads to positive frequency dependence and signal uniformity. However, when two morphs of the same species vary greatly in conspicuousness, the maintenance of both cryptic and conspicuous forms in profitable prey populations remains enigmatic. Using the white and melanic morphs of the invasive box tree moth (Cydalima perspectalis) presented at three different frequencies, we investigate (a) the palatability of caterpillars and adult moths to birds, (b) predation rates on the less conspicuous melanic morph, and (c) the role of frequency dependence in balancing morph frequencies. Our results show that caterpillars are distasteful for birds but not adult moths that are fully palatable. We found that the less conspicuous, melanic morph, benefits from reduced predation due to its lower detectability. The more conspicuous, white morph, instead, is more predated and is best off when common, suggesting positive frequency dependence. These results offer new insights into the evolution of color polymorphism and prey defenses in a polymorphic moth species. Further investigation is required to understand the role of different predation regimes on the maintenance of the polymorphism in this species and test whether additional selection pressures operate in natural populations.
ABSTRACT
Four new species of Indasclera vihla, 1980 are described and illustrated: Indasclera bipartita n. sp. from Laos, I. hajeki n. sp. from Malaysia, I. pusilla n. sp. and I. thailandica n. sp., both from Thailand. In addition, a dichotomous key for the I. haemorrhoidalis species group is given.
Subject(s)
Coleoptera , Animals , Animal DistributionABSTRACT
This paper is the first to deal with the false-blister beetle of the sultanate of Oman: it provides an overview of the biogeography of the country and an annotated checklist of the eight known species, four of which are new for Oman. In addition, a new species, Probosca (Proboxantha) coniuncta n. sp. is described.
Subject(s)
Coleoptera , Animals , OmanABSTRACT
Longhorn beetles are among the most important groups of invasive forest insects worldwide. In parallel, they represent one of the most well-studied insect groups in terms of chemical ecology. Longhorn beetle aggregation-sex pheromones are commonly used as trap lures for specific and generic surveillance programs at points of entry and may play a key role in determining the success or failure of exotic species establishment. An exotic species might be more likely to establish in a novel habitat if it relies on a pheromone channel that is different to that of native species active at the same time of year and day, allowing for unhindered mate location (i.e., pheromone-free space hypothesis). In this study, we first tested the attractiveness of single pheromone components (i.e., racemic 3-hydroxyhexan-2-one, racemic 3-hydroxyoctan-2-one, and syn-2,3-hexanediol), and their binary and tertiary combinations, to native and exotic longhorn beetle species in Canada and Italy. Second, we exploited trap catches to determine their seasonal flight activity. Third, we used pheromone-baited "timer traps" to determine longhorn beetle daily flight activity. The response to single pheromones and their combinations was mostly species specific but the combination of more than one pheromone component allowed catch of multiple species simultaneously in Italy. The response of the exotic species to pheromone components, coupled with results on seasonal and daily flight activity, provided partial support for the pheromone-free space hypothesis. This study aids in the understanding of longhorn beetle chemical ecology and confirms that pheromones can play a key role in longhorn beetle invasions.
Subject(s)
Coleoptera/physiology , Insect Control , Sex Attractants , Animals , Introduced Species , Italy , Seasons , Species SpecificityABSTRACT
A new Ischnomera from northern Sicily is described. Besides this species, in the western Mediterranean I. xanthoderes complex were distinct one species from the Iberian peninsula and southern France (I. xanthoderes), and one from northwestern Africa (I. tenietensis). All species are figured and a key to the species is published.
