The lipids of the common house cricket,Acheta domesticus L. I. Lipid classes and fatty acid distribution

The lipidome of an omnivorous insect responds to diet composition and social environment

Lipids are biomolecules with essential roles in metabolic processes, signaling, and cellular architecture. In this study, we investigated changes in the lipidome of the house cricket Acheta domesticus subjected to diets of different nutritional composition (i.e., protein to carbohydrate ratio) and two distinct social environments (i.e., solitary or in groups). We measured relative abundances of 811 lipid species in whole-body cricket samples using flow injection analysis coupled to tandem mass spectrometry. We assessed differences in the relative abundances of lipid species induced by diet composition and social environment in female and male A. domesticus. Additionally, we performed a functional analysis of the lipids with significant differences using a recently developed database. We found that most differences in the relative abundances of lipid species were explained by sex alone. Furthermore, the lipidome of female A. domesticus was responsive to diet composition. Females fed with the balanced diet had an even higher abundance of lipids involved in lipid storage than their counterparts fed with a protein-rich diet. Interestingly, the male cricket lipidome was not responsive to diet composition. In addition, the social environment did not induce significant changes in the lipid profile neither in female nor in male crickets.

Comparative nutrient analysis of four species of cockroaches used as food for insectivores by life stage, species, and sex

A variety of insects are fed to insectivorous animals; however, nutritional analyses are often limited to adult life stages. Four species of nymph and adult female and male cockroaches (Blaberus giganteus, Blaptica dubia, Blatta lateralis, and Gromphadorhina portentosa) were analyzed for moisture, crude protein (CP), acid detergent fiber (ADF), fat, ash, and mineral content. The small sample size of this study precluded statistical analyses, however comparatively, CP in adult B. lateralis and B. dubia was greater than the CP in nymphs of the same species. Adult and nymph B. dubia had the greatest CP (96.6% and 65.3%, respectively) compared to the other three species. Inversely, fat content in adult B. lateralis and B. dubia was lower than that of nymphs of the same species. All adults contained similar levels of ADF, yet adult B. giganteus had greater ADF than nymphs; conversely, B. lateralis and B. dubia adults had less ADF than nymphs. There were differences noted in mineral parameters among the four species and life stages. Adult B. giganteus had less Ca than G. portentosa, and the lowest Ca content of the four species of nymphs and adults analyzed. This study underscores the differences in nutrient content with respect to life stage and species in previously understudied cockroaches to improve nutrient intake in captive insectivores.

Insects: A Potential Source of Protein and Other Nutrients for Feed and Food

Sustainable production of healthy food for a growing global population, in the face of the uncertainties of climate change, represents a major challenge for the coming decade. Livestock provide food with high nutritional value but are frequently fed on human-edible crops and are associated with significant production of greenhouse gases. Recent years have seen increasing interest in the farming of insects as a sustainable source of human food, or as a replacement of ingredients such as soya or fishmeal in the feeds of terrestrial livestock or fish. This review provides an overview of insect physiology and growth regulation, considers the requirements for insect farming and mass production, and summarizes the nutritional value of the 10 most commonly studied insect species, before reviewing the literature on the use of insects as feed and food. We highlight the challenges required to develop a sustainable, safe, and affordable insect farming industry.

Identification and Quantification of Fatty Acids in T. viridissima, C. biguttulus, and C. brunneus by GC-MS

Fatty acid (FA) profiles of the species Tettigonia viridissima, Chorthippus biguttulus, and Chorthippus brunneus were determined and quantitated. Extracted lipids were derivatized into FA methyl esters (FAMEs) prior to analysis by GC-MS. A total of 37 different FAs were identified in T. viridissima, yielding a total FA content of 10.4 g/100 g of dry matter. The contents of saturated FAs, monounsaturated FAs, and polyunsaturated FAs were 31.1, 35.9, and 33.0%, respectively. Lipids from T. viridissima were also fractioned into neutral lipids, free fatty acids, and polar lipids by offline solid phase extraction. For C. brunneus and C. biguttulus, 33 FAs were identified, yielding a total FA content of 6.14 g/100 g of dry matter. SFAs, MUFAs, and PUFAs, respectively, constituted 32.7, 25.1, and 42.1% of the total FA content. The contents of MUFAs, PUFAs, n-3 FAs, and n-6 FAs of each species, and the n-6/n-3 ratio, were subsequently discussed.

Ethyl decanoate as a major component in the defensive secretion of two new zealand aleocharine (staphylinidae) beetles-Tramiathaea cornigera (broun) andThamiaraea fuscicornis (broun)

The defensive secretions of bothTramiathaea cornigera andThamiaraea fuscicornis contain undecane, toluquinone, ethyl decanoate and smaller amounts of other esters. The presence of esters particularly ethyl decanoate as a major component sets these two beetles apart chemically not only among the staphylinids but also within the subfamily Aleocharinae.

(Z)-4-Tridecenal, a pheromonally active air oxidation product from a series of (Z,Z)-9,13 dienes inMacrocentrus grandii Goidanich (Hymenoptera: Braconidae)

(Z)-4-Tridecenal was identified as a sex pheromone component ofMacrocentrus grandii, a larval parasitoid of the European corn borer. The aldehyde was found to be a common air oxidation product from a series of (Z,Z)-9,13-dienes of 27-33, 35, 37, 39, and 41 carbon atoms in female wasps. Synthetic (Z)-4-tridecenal and (Z,Z)-9,13-heptacosdiene each elicited flight initiation, upwind anemotaxis, casting, landing on the source, walking, wing fanning, and copulatory attempts by male wasps in a wind-tunnel. Field studies demonstrated that both compounds are synergized by a more polar component. Synthetic (E)-4-tridecenal was not attractive.

The lipids of the common house cricket,Acheta domesticus L. III. Sterols

Sterols constitute 1.95% of the total extractable lipids ofAcheta domesticus L., of which 18% are esterified. The free sterols consist of cholestane-3beta-ol (0.5%), Delta(5)-cholestene-3beta-ol (83.5%), Delta(7)-cholestene-3beta-ol (2.3%) Delta(5,7)-cholestadiene-3beta-ol (3%), Delta(5,22)-cholestadiene-3beta-ol (4%), Delta(5,7,22)-cholestatriene-3beta-ol (0.2%), campestane-3beta-ol (0.03%), Delta(5)-campestene-3beta-ol (1.0%), Delta(7)-campestene-3beta-ol (trace), Delta(5,7)-campestadiene-3beta-ol (0.2%), stigmastane-3beta-ol (0.09%), Delta(5)-stigmastene-3beta-ol (2.1%), Delta(7)-stigmastene-3beta-ol (0.04%), Delta(5,7)-stigmastadiene-3beta-ol (0.4%), Delta(5,22)-stigmastadiene-3betaol (0.1%). The same sterols are present in the esterified sterol fraction. Delta(7)-Sterols and Delta(5,7)-sterols are present in significantly larger amounts in the esterified fraction than in the free sterol fraction. By a comparison with the sterols of the cricket food, it is clear thatA. domesticus is capable of removing methyl and ethyl groups from C-24 of sterols of the campestane and stigmastane type. The ability to introduce a Delta(7) double bond into saturated and Delta(5)-sterols is indicated, and it is suggested that Delta(7)-sterols of the C(27), C(28), and C(29) sterol series may be intermediates in the conversion of Delta(5)-sterols to Delta(5,7)-sterols.