Food security is a problem in many developing and less developed countries due to increase in human population and decrease in crop productivity and food availability. Edible insects are a natural renewable resource of food providing carbohydrates, proteins, fats, minerals and vitamins. As such, entomophagy is common in ethnic groups in South America, Mexico, Africa and Asia, where indigenous insects are easily available and are consumed in various forms (raw/processed) or used as an ingredient or supplement in modern recipes. Entomophagy therefore offers an opportunity to bridge the protein gap of human foods irrespective of a few constraints that are discussed. Concerning food security, more attention is needed to assess and revalidate entomophagy in the context of modern life. Further research would be necessary to exploit insect biodiversity and ethno-entomophagy, stop overexploitation of these insects, and initiate actions for insect conservation.

The amino acid, fatty acid and mineral composition of Aspongubus viduatus F. (melon bug) and Agonoscelis pubescens (Thunberg) (sorghum bug) were investigated. The approximate analyses of A. viduatus and A. pubescens adults showed 8.3 and 7.6% moisture, 27.0 and 28.2% crude protein, 54.2 and 57.3% fat and 3.5 and 2.5% ash on a dry-matter basis, respectively. The bug protein contained 16 amino acids, including all of the essential ones. Compared with the amino acid profile recommended by FAO/WHO, the protein was of medium quality. The most predominant fatty acids in melon bug oil were oleic, palmitic, linoleic and linolenic acids, viz. 45.5, 31.3, 4.9 and 0.48%, respectively, and in sorghum bug 41.15, 11.41, 35.28 and 1.28%, respectively. The mineral analysis indicated high P and K content. Scanning electron microscopy was used to study ground insect structure before and after oil extraction. Micrographs of full-fat ground insects were different from defatted ones.

A survey on the occurrence of entomopathogenic nematodes (EPNs) was conducted in selected banana fields from three regions in Tanzania, namely Mbeya (Southern Highlands), Morogoro (Lowland) and Pwani (Coast). The main objective of this study was to isolate EPNs naturally occurring in banana fields in Tanzania and to test their effect on banana weevil (Cosmopolites sordidus Germar 1824). We report for the first time the presence of EPNs in Tanzania where four (4.4%) out of 90 samples contained nematodes in the genera Steinernema and Heterorhabditis. EPNs were only isolated in the coastal region in soils with a high sand content. The virulence of nine EPN isolates was tested against larvae and adults of C. sordidus. All isolates caused mortality of the larval stages, whereas the adults appeared resistant to nematode infection. Larval mortality was found to increase significantly with increasing nematode dose. It was also shown that nematodes were able to penetrate and establish in the banana weevil larvae in increasing numbers with increasing nematode dose. The study indicates the potential for including EPNs in management strategies of banana weevil.

Successful mass production of biocontrol agents is a prerequisite to their effective use in the field. Thus in the present study the suitability of ten aphid species of a ladybird beetle Anegleis cardoni (Weise) in terms of growth, development, survival and mortality life table attributes was assessed for the purpose of mass production. The study revealed that the developmental duration of the immature stages of A. cardoni was shortest when fed on Uroleucon compositae (Theobald), Rhopalosiphum maidis (Fitch), Hyadaphis coriandri (Das) and Myzus persicae (Sulzer) in comparison with other aphid species. Immature survival, development rate, adult weight and growth index were also highest when A. cardoni larvae were fed on these aphids, while lowest when fed on Hysteroneura setariae (Thomas) and Ceratovacuna silvestri (Takahashi). Any larva of A. cardoni did not reach adult stage when fed on Aphis nerii Boyer de Fonscolombe; therefore it may be considered as a toxic prey. Life table data revealed that the overall mortality prior to adult stage was lowest in U. compositae and highest in C. silvestri. The first instars suffered the highest mortality in comparison with other instars on all the aphid species tested. However, the life expectancy for each aphid species as prey revealed a continuous decline with the advancement of age. Thus among all the ten aphid species tested, U. compositae, R. maidis, H. coriandri and M. persicae were found equally suitable for mass production of A. cardoni.

The structure of two compounds extracted from the leaves of Vitex negundo L., their repellent activity and toxicity against three strains of Tribolium castaneum (Herbst) were elucidated. Two compounds were purified and a residual film bioassay was used to evaluate the toxicity to adult T. castaneum. Mortality was recorded 24, 48 and 72 h post-exposure to compounds. The repellency activity of methanol extract was tested by using nine concentrations. Each dose was applied on a half circle of the filter paper, keeping the other part untreated. Insects released on treated filter paper were assessed for repellency up to 5 h. Two bioactive compounds, 22,23-dihydro-α-spinasterol-β-d-glucoside and salicylic acid were isolated from the methanolic leaf extracts by column chromatography and thin-layer chromatography. Their structures were elucidated by various spectroscopic methods. Compound 22,23-dihydro-α-spinasterol-β-d-glucoside is the first report from this plant. Both compounds showed insecticidal activity and the leaf extracts caused 100% repellency in the three tested strains of T. castaneum. Both compounds showed toxicity to T. castaneum, but compound 22,23-dihydro-α-spinasterol-β-d-glucoside was more potent. Its potential future use as herbal insecticide against T. castaneum is discussed.

Inter simple sequence repeats (ISSR) and random amplified DNA polymorphism (RAPD) markers were used to estimate the genetic diversity among 14 tropical silkworm races (Bombyx mori L.) for identifying potential parents to be used for hybrid preparation for commercial exploitation. High polymorphism (70.91 and 74.70%) was revealed by ISSR and RAPD markers. The dendrograms generated, using unweighted pair group method using arithmetic average from these markers, grouped the 14 silkworm races into two major groups, which corroborates the differences in cocoon characteristics. Discriminant function analysis of ISSR and RAPD markers identified three functions for cocoon weight and two functions for shell weights, respectively. Step-wise multiple regression analysis identified six ISSR markers (834500, 8841700, 8841850, 8271500, 8401500 and 7891250) and seven RAPD markers (834500, 885900, 8101400, 884900, 8361500, 7891250 and 7621700) significantly associated with cocoon and shell weights. The genetically divergent parents, identified through this study, can be used for the preparation of hybrids for commercial utilization. Similarly, the DNA markers identified can be utilized for marker-assisted selection along with those identified through quantitative trait locus mapping by others. Thus the information generated in this study is useful in silkworm breeding programmes in the tropical sericulture industry.

The citrus swallowtail Papilio demoleus L. is a serious pest of citrus in many regions of the world. We evaluated the effects of pyriproxyfen, a juvenile hormone agonist, on late-stage larval and pupal development of the pest. Fourth and fifth instars, as well as freshly formed prepupae were treated topically with concentrations of 7.5–60 μg/μl of the juvenile hormone analogue. Effects included prolongation of larval duration, delay in larval–larval and larval–pupal ecdysis, mortality, formation of mosaics with larval, pupal and adult characteristics, decreased and imperfect pupation, and complete inhibition of emergence. These results demonstrate that pyriproxyfen has an adverse effect on the development and metamorphosis of the citrus swallowtail, and further work is recommended, including laboratory and field studies.

The moth Pareuchaetes pseudoinsulata Rego Barros, whose host plant is the invasive alien plant Chromolaena odorata (L.) King and Robinson, was recently discovered in Uson (6° 14′ 30.77″ N, 6° 04′ 41.37″ E), Evbuabogun (6° 15′ 39.33″ N, 5° 38′ 58.29″ E) and Ekae (6° 15′ 34.90″ N, 5° 37′ 19.75″ E) villages in southern Nigeria after its first release as a biological control agent in that country in 1972. The moth seemed to become more abundant as the rainy season progressed. Studies on some aspects of its biology and behaviour were conducted both in the laboratory and in the field. Females laid eggs on the undersides of C. odorata leaves and on the walls of rearing cages. Female pupae were significantly (P < 0.001) larger than the male ones. Also, adult female wingspan was significantly (P < 0.001) longer compared with that of the males. Adults lived for an average of 4.8 ± 0.01 days and they were active at night, when there was good light intensity. Observations on the behaviour and some aspects of the biology and behaviour are discussed.