Ecotoxicology of human pharmaceuticals.

Divergent natural selection has been shown to promote speciation in many taxa. However, although divergent selection often initiates the process of speciation, it often fails to complete it. Several time-based, geographic and genetic factors have been recognized to explain this variability in how far speciation proceeds. We review here recent evidence indicating that variability in the completeness of speciation can also be associated with the nature of divergent selection itself, with speciation being greatly promoted by (i) stronger selection on a given, single trait (the 'stronger selection' hypothesis) and (ii) selection on a greater number of traits (the 'multifarious selection' hypothesis). However, evidence for each selective hypothesis is still scarce, and further work is required to determine their relative importance.

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Ecological explanations for (incomplete) speciation

Lipids of the insect cuticle: origin, composition and function

Review on the use of insects in the diet of farmed fish: Past and future

Terrestrial biodiversity is dominated by plants and the herbivores that consume them, and they are one of the major conduits of energy flow up to higher trophic levels. Here, we address the processes that have generated the spectacular diversity of flowering plants (>300,000 species) and insect herbivores (likely >1 million species). Long-standing macroevolutionary hypotheses have postulated that reciprocal evolution of adaptations and subsequent bursts of speciation have given rise to much of this biodiversity. We critically evaluate various predictions based on this coevolutionary theory. Phylogenetic reconstruction of ancestral states has revealed evidence for escalation in the potency or variety of plant lineages' chemical defenses; however, escalation of defense has been moderated by tradeoffs and alternative strategies (e.g., tolerance or defense by biotic agents). There is still surprisingly scant evidence that novel defense traits reduce herbivory and that such evolutionary novelty spurs diversification. Consistent with the coevolutionary hypothesis, there is some evidence that diversification of herbivores has lagged behind, but has nevertheless been temporally correlated with that of their host-plant clades, indicating colonization and radiation of insects on diversifying plants. However, there is still limited support for the role of host-plant shifts in insect diversification. Finally, a frontier area of research, and a general conclusion of our review, is that community ecology and the long-term evolutionary history of plant and insect diversification are inexorably intertwined.

https://www.pnas.org/content/pnas/106/43/18054.full.pdf

Macroevolution and the biological diversity of plants and herbivores

A new rapid procedure for preparing soft internal tissues from insects that allows air drying was found to compare favorably with tissues prepared by critical point drying. In the new procedure, tissues were fixed in 1% glutaraldehyde, dehydrated through a graded ethanol series, immersed in hexamethyldisilazane (HMDS) for 5 minutes, and air dried. Tissues prepared by both the HMDS treatment and by critical point drying were coated with gold for scanning electron microscopy. Tissues prepared by the HMDS treatment did not shrink or distort upon air drying and excellent surface detail was preserved. The HMDS treatment required about 5 minutes, whereas the critical point drying procedure required about 1.5 hours.

A New Method Using Hexamethyldisilazane for Preparation of Soft Insect Tissues for Scanning Electron Microscopy

Embryogenesis Digestion Nutrition Integument Hormones and Development Diapause Intermediary Metabolism Neuroanatomy Neurophysiology Muscles Flight Sensory Systems Vision Circulatory System Immunity Respiration Excretion Pheromones Reproduction Appendix

Insect Physiology and Biochemistry

Attachment of Metarhizium anisopliae to the southern green stink bug Nezara viridula cuticle and fungistatic effect of cuticular lipids and aldehydes

Responses of seven species of pine-infesting beetles to traps baited with either turpentine, ethanol, turpentine and ethanol released from separate dispensers, or a 1:1 solution of turpentine and ethanol released from one dispenser were assessed in three field experiments. The weevil species, Pachylobius picivorus (Germar), and the cerambycid pine sawyer, Monochamus carolinensis (Olivier), were attracted to turpentine and were unaffected by the addition of ethanol. The ambrosia beetle, Xyleborus affinis Eichhoff, responded to ethanol alone but was not attracted to turpentine, nor did the presence of turpentine significantly affect its response to ethanol. The remaining four species displayed responses to turpentine that were enhanced by the addition of ethanol, but in different ways according to the method of deployment. Hylobius pales (Herbst) weevils and M. titillator (F.) sawyers displayed greatest attraction to turpentine and ethanol whether they were released from side-by-side dispensers or as a solution from one dispenser. The black turpentine beetle, Dendroctonus terebrans (Olivier), displayed the highest response to turpentine and ethanol in solution. The ambrosia beetle, X. pubescens Zimmermann, responded in low numbers to turpentine or ethanol deployed singly, but displayed an enhanced response (20-fold increase) to turpentine and ethanol deployed side-by-side and an even greater response (60-fold increase) to a solution of turpentine and ethanol. Reasons for increased responses by some species to a solution of turpentine and ethanol over the two released separately are not clear; they may lie in different dosages or evaporation rates of volatiles in the field. Laboratory analyses of trapped headspace volatiles from dispensers containing only turpentine and those containing a solution of turpentine and ethanol revealed no differences in the amounts of four principal monoterpene hydrocarbons (α-pinene, camphene, β-pinene, and limonene) released over time. The synergistic effect of turpentine and ethanol for some species and not others may point to ecological differences between species with regard to the condition of preferred host material.

Synergism of Turpentine and Ethanol as Attractants for Certain Pine-Infesting Beetles (Coleoptera)

Male Anastrepha suspensa (Loew) (Diptera: Tephritidae) release one or more volatile pheromones that attract females in laboratory assays. Males probably release the pheromone(s) while distending the pleural region of abdominal segments 3, 4, and 5, and an anal pouch. Males produce bursts of rapid wing fanning while distending the pouches. Organic solvent extracts of males and pieces of absorbent paper left for several days in male cages also attract females. Maximum attraction of 45% of females tested occurs when males and females are 11 days old. The ovaries and terminal oocytes also mature in females at about 11 days. The bioassay apparatus is described.

James L. Nation

Papers

A New Method Using Hexamethyldisilazane for Preparation of Soft Insect Tissues for Scanning Electron Microscopy

Insect Physiology and Biochemistry

Attachment of Metarhizium anisopliae to the southern green stink bug Nezara viridula cuticle and fungistatic effect of cuticular lipids and aldehydes

Synergism of Turpentine and Ethanol as Attractants for Certain Pine-Infesting Beetles (Coleoptera)

Courtship Behavior and Evidence for a Sex Attractant in the Male Caribbean Fruit Fly, Anastrepha suspensa