Defensive adaptations of eggs and adults ofGastrophysa cyanea (Coleoptera: Chrysomelidae)

Analyses of head and thorax in Eupomphini (Meloidae) suggest that complex behaviors are not associated to changes in general shape

Our results reject an association between general shape of head and thorax with defensive and courtship behaviors in the studied Eupomphini blister beetles. Instead we found that shape of thorax and head radiated in all directions of the morphospace. We also identified a radical separation between two lineages that could represent future evolutionary constraints for thorax evolution.

Egg toxic compounds in the animal kingdom. A comprehensive review

Covering: 1951 to 2022Packed with nutrients and unable to escape, eggs are the most vulnerable stage of an animal's life cycle. Consequently, many species have evolved chemical defenses and teamed up their eggs with a vast array of toxic molecules for defense against predators, parasites, or pathogens. However, studies on egg toxins are rather scarce and the available information is scattered. The aim of this review is to provide an overview of animal egg toxins and to analyze the trends and patterns with respect to the chemistry and biosynthesis of these toxins. We analyzed their ecology, distribution, sources, occurrence, structure, function, relative toxicity, and mechanistic aspects and include a brief section on the aposematic coloration of toxic eggs. We propose criteria for a multiparametric classification that accounts for the complexity of analyzing the full set of toxins of animal eggs. Around 100 properly identified egg toxins are found in 188 species, distributed in 5 phyla: cnidarians (2) platyhelminths (2), mollusks (9), arthropods (125), and chordates (50). Their scattered pattern among animals suggests that species have evolved this strategy independently on numerous occasions. Alkaloids are the most abundant and widespread, among the 13 types of egg toxins recognized. Egg toxins are derived directly from the environment or are endogenously synthesized, and most of them are transferred by females inside the eggs. Their toxicity ranges from ρmol kg^-1 to mmol kg^-1, and for some species, experiments support their role in predation deterrence. There is still a huge gap in information to complete the whole picture of this field and the number of toxic eggs seems largely underestimated.

Developmental Biology and Effects of Adult Diet on Consumption, Longevity, and Fecundity of Colaspis crinicornis (Coleoptera: Chrysomelidae)

The chrysomelid beetle Colaspis crinicornis Schaeffer (Coleoptera: Chrysomelidae) occurs primarily in the Great Plains region of the United States. Little is known about the biology and ecology of this species, but over the last decade, it has become increasingly common in the corn, Zea mays L., and soybean, Glycine max (L.) Merrill, agroecosystem of southeastern Nebraska. As part of a larger comprehensive project to understand the natural history and pest potential of this species, laboratory experiments were conducted to study the developmental biology, morphological characters of immature stages, and the effect of adult diet on consumption, longevity, and fecundity. Females readily deposited egg clusters in the soil, and percentage egg hatch was high under laboratory conditions. Larvae and pupae were confirmed to be soil-dwelling stages. C. crinicornis has relatively short egg, pupal, and adult stages with the majority of its life cycle spent in the larval stage. Results of choice and no-choice adult feeding experiments indicate that diets of corn or soybean leaves did not significantly affect consumption, longevity, or fecundity of adult C. crinicornis, suggesting that corn and soybean leaves are similarly suitable food sources for adults. The ability to effectively utilize tissues from very different plant families as adult food sources suggests that C. crinicornis is polyphagous in the field.

Dependence of necrophoric response to oleic acid on social context in the ant,Pogonomyrmex badius

The response of the southern harvester ant,Pogonomyrmex badius, to oleic acid was found to depend on social context. Social context was specified as the number of ants engaging in each of five categories of behavior. When a large percentage of the colony is doing midden work or nest maintenance, papers treated with oleic acid are taken to the midden, as previously reported. However, when a large percentage of the colony is foraging or convening, treated papers are taken into the nest as if they were food items.

Anthraquinones in different developmental stages ofGaleruca tanaceti (Coleoptera, Chrysomelidae)

The overwintering eggs and the larvae of the leaf beetleGaleruca tanaceti (L.) contain hydroxylated anthraquinones. In both developmental stages, l,8-dihydroxy-3-methylanthraquinone (= chrysophanol) and 1,8-di-hydroxyanthraquinone (= chrysazin) were detected by GC-MS and GC-FTIR analyses. In the eggs, chrysazin was found only in traces. Anthraquinones were also present in ovaries and hemolymph of gravid females, which were investigated in order to examine the incorporation of these substances into the eggs. Neither in acidified nor in nonacidified extracts of the host plantsTanacetum vulgäre L. andAchillea millefolium L. were anthraquinones found. The activity of these anthraquinones as chemical defense substances was proved in bioassays with the antMyrmica ruginodis NYL. Further possible biological significances of anthraquinones are discussed.

Ant repellent effect of the sternal gland secretion ofPolistes dominulus (Christ) andP. sulcifer (Zimmermann). (Hymenoptera: Vespidae)

The long-chain carboxylic acids identified in the sternal gland secretion ofPolistes dominulus andP. sulcifer females were tested individually on three species of ants,Crematogaster scutellaris, Formica cunicularia, andLasius sp., in order to verify if they have a repellent effect. The unsaturated acids (palmitoleic, linoleic, and oleic) act as repellents of all three ant species, while the saturated acids (lauric, myristic, palmitic, and stearic) have no effect. The mixture reproducing the secretion of the sternal glands ofP. dominulus maintained its repellency for at least four days.

Free fatty acids in the cuticular and internal lipids of Calliphora vomitoria and their antimicrobial activity

The cuticular and internal lipid composition in Calliphora vomitoria larvae, pupae, and male and female adults was studied. The free fatty acid (FA) compositions of the lipids were chemically characterized using gas chromatography (GC) and gas chromatography-electron impact mass spectrometry (GC-MS). Analyses of cuticular extracts from larvae, pupae, and male and female adults revealed that the carbon numbers of the acids ranged from C7:0 to C22:0, from C8:0 to C24:0, from C7:0 to C24:0 and from C7:0 to C22:0 respectively. The internal lipids of C. vomitoria larvae, pupae, male and female adults contained FAs ranging from C8:0 to C20:0, from C9:0 to C22:0, from C8:0 to C24:0 and from C9:0 to C22:0 respectively. Nine FAs with odd-numbered carbon chains from C7:0 to C21:0 were identified in the cuticular lipids of the larvae. The internal lipids of C. vomitoria larvae contained 8 odd-numbered FAs ranging from C9:0 to C19:0. Eight odd-numbered FAs from C9:0 to C21:0 were identified in the cuticular and internal lipids of pupae, while nine such FAs were found in the cuticular lipids of male and female adults. The internal lipids of adult males and females respectively contained nine and seven odd-numbered FAs, while both larvae and pupae contained eight such compounds. Eight unsaturated FAs were identified in the cuticular lipids of larvae, adult males and females and also in the internal lipids of females. Seven unsaturated FAs were identified in the cuticular lipids of pupae. The internal lipids of larvae, pupae and males contained 10, 11 and 12 unsaturated FAs respectively. Developmental changes were found both in the amounts of extracted cuticular and internal FAs and in their profiles. Four cuticular FAs (C7:0, C9:0, C10:0 and C15:1), identified as being male-specific, were either absent in the female cuticle or present there only in trace amounts. Cuticular and internal extracts obtained from larvae, pupae, adult males and females were tested for their potential antimicrobial activity. The minimal inhibitory concentrations of extracts against reference strains of bacteria and fungi were determined. Antimicrobial activity was the strongest against Gram-positive bacteria; Gram-negative bacteria, on the other hand, turned out to be resistant to all the lipids tested. Overall, the activities of the internal lipids were stronger. All the lipid extracts were equally effective against all the fungal strains examined. In contrast, crude extracts containing both cuticular and internal lipids displayed no antifungal activity against the entomopathogenic fungus Conidiobolus coronatus, which efficiently killed adult flies, but not larvae or pupae.