Notes on the biological development of the darkling beetle Blaps nefrauensis nefrauensis Seidlitz, 1893 (Coleoptera: Tenebrionidae)

Several endemic species of Blaps occur in Tunisia, and the species Blaps nefrauensis nefrauensis has been reported in Moulares (urban zone in west-central Tunisia), where it lives and reproduces in home gardens and old buildings. The aim of this work is to study the life cycle of the darkling beetle, considering both field and laboratory rearing conditions. As a result, the beetle species has different developmental stages (egg, larva, prepupa, pupa, and adult) that last about 15 months. Each year during the same period, adults emerge (early summer) and expire (late autumn), larvae hatch (late summer) and pupate (early summer). There is only one generation per year. Females began laying eggs in late July. The eggs were ovoid, white, and about 2.7 mm in length and 1.5 mm in width. Embryogenesis took an average of nine days. The first instar larvae were at initially only 4.5 mm long and ivory white in color. A brief description of the newly egg hatched larva was provided; thus, the nerve fibers innervating the apical setae in the antennae and ligula were detected. Further light microscopic examination of the embryo before hatching from the egg pointed out that the antennal sensilla are protected during the embryogenesis stage.

Notes on the life history of Aguna megacles megacles (Mabille, 1888) (Lepidoptera: Hesperiidae: Eudaminae) feeding on Bauhinia species in the State of Alagoas, Brazil

Eudaminae Mabille, 1877 (Hesperiidae), recognized as subfamily recently, is rich in Brazil. It is along the Neotropical Region where a significant part of the diversity is found, however, information that involves the biology of species is poorly yet. This paper gathers new bioecological data of an Aguna species from the municipality of Maceió (Alagoas, Brazil), close to the Environmental Protection Area of “Catolé” and “Fernão Velho”, a remnant of Atlantic Forest. Leaves containing eggs were collected in a peri-urban area (9° 33’ 26” S, 35° 46’ 36” W) and taken to laboratory to observe post-embryonic development. Larvae were also collected from another host plant in an intra-urban area (9° 39’ 40” S, 35° 41’ 58” W). The specimens were identified as Aguna megacles megacles (Mabille, 1888) and the two Fabaceae as Bauhinia pentandra (Bong.) D. Dietr. and Bauhinia monandra Kurz. from exsiccates deposited at the Herbarium. Rearing from the eggs collected on B. pentandra exposes a post-embryonic development that lasted 53.4 days for six larval instars individuals, and 46 days for the five larval instars specimen. The larvae built a shelter since the first instar and in laboratory conditions they preferred pupate on the base of the cage. This is the first report of development features for A. m. megacles, including six and five larval instars, as well as a new locality for the State of Alagoas, and two more host plants of Bauhinia suggesting specialist behavior.

Predatory Ability of Harmonia axyridis (Coleoptera: Coccinellidae) and Orius sauteri (Hemiptera: Anthocoridae) for Suppression of Fall Armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae)

The lepidopteran pest, Spodoptera frugiperda (JE Smith), spread rapidly after its first detection in China and has caused significant yield loss to maize production in the southwestern part of the country. Although natural enemies of S. frugiperda are present in the field, biological control using naturally distributed predators is ineffective because their underlying populations are too low. To enhance our understanding of the potential role of natural enemies in regulating this invasive pest, functional response experiments were conducted to quantify the response of two predators, Orius sauteri (Poppius) (Hemiptera: Anthocoridae) and Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), in terms of consumption of S. frugiperda. Experimental results revealed that the predatory effects of nymphs of O. sauteri and H. axyridis on the eggs and larvae of S. frugiperda fitted Holling’s Type II functional response model. Importantly, the theoretical maximum number of prey consumed per day (Na-max), the instantaneous attack rate (a′) and the handling time (Th) of O. sauteri nymphs on S. frugiperda eggs were 15.19, 0.7444 and 0.049 d, respectively; and the parameters on first instar larvae of S. frugiperda were 700.24, 0.5602 and 0.0008 d, respectively. These data contrast to those of H. axyridis, where the Na-max, a′ and Th of adults on eggs of S. frugiperda were 130.73, 1.1112 and 0.085 d, respectively, and on the first instar larvae of S. frugiperda were 1401.1, 0.8407 and 0.0006 d, respectively. These results revealed that H. axyridis is a highly voracious predator of the eggs and young larvae of S. frugiperda and O. sauteri could also be used as biocontrol agent of this pest. Our work provides a theoretical framework for the application of natural enemies to control S. frugiperda in the field. Further research is required to strategize conservation biological control approaches in the field to increase populations of these predators and enhance the suppression of S. frugiperda.

The larval structures and bionomics of Idgia iriomoteana (Coleoptera: Prionoceridae)

The life cycle, bionomics and mature larval structures of the Japanese prionocerid species, Idgia iriomoteana Nakane, 1980 were investigated in captivity. The results showed that I. iriomoteana has the following characteristics: (1) the larval morph is less advanced in terms of miniaturization, and larvae pass seven larval molts before they pupate; (2) the life cycle is univoltine with summer, not winter, dormancy; (3) the first instar larvae are larger than the size of the egg, but foetomorphic larval instar (which is observed in the Melyridae: Malachiinae) is not shown. Based on comparison with melyrid species, the degree of miniaturization, dormancy behaviour, adaptation to the tropical and subtropical climates and the adaptive significance of a large first instar larva are all discussed. This study is the first to report the complete life cycle of a member of the family Prionoceridae.

Systematic position of Bombyx incomposita (Lepidoptera: Bombycidae), with notes on its immature biology and hostplant association

The immature stages, morphology, and systematic position of Bombyx incomposita (van Eecke, 1929) are reported. The morphology of larva was investigated using scanning electron microscopy, and the phylogeny was inferred using six genes (COI, CAD, EF-1α, GAPDH, RpS5, and wgl). The molecular phylogeny strongly supported that B. incomposita is sister to B. huttoni Westwood, 1847. The divergence of the COI barcode, phylogenetic reconstruction, and difference in immature stages support the current classification, in which the species incomposita belongs to the genus Bombyx. We give illustrations of male and female genitalia and briefly discuss the utility of the chaetotaxy of the first instar larvae on taxonomy of silkmoths. The SV group bears six setae in B. mandarina, but eight in B. incomposita. The L1 bears three setae in Rotunda, but just single seta in Bombyx.

Revision of the Neotropical genus Sturmiodexia Townsend, 1919 (Diptera: Tachinidae), with a new synonymy and combinations

The monotypic genus Sturmiodexia Townsend, 1919 is a poorly known Neotropical taxon. Herein a new generic synonymy is proposed for this genus: Platyrrhinodexia Townsend, 1927 syn. nov. Two new combinations are assigned for Sturmiodexia: S. moyobambensis (Townsend, 1929) comb nov. and S. punctulata (Townsend, 1927) comb nov. Redescriptions were done for S. punctulata, S. rubescens Townsend 1919 and S. muscaria (Walker 1853). With these new propositions, Sturmiodexia is left with four species. In addition, the male and female terminalia, and the first instar larva, are described and illustrated for the first time for S. punctulata. Finally, a diagnose for Sturmiodexia and a key to all species is given.

BIOLOGICAL TRAITS OF BEAN FLOWER THRIPS, Megalurothrips usitatus (THYSANOPTERA: THRIPIDAE) REARED ON MUNG BEAN

The bean flower thrips, Megalurothrips usitatus is a major pest of mung bean that causes flower dropping and significant yield loss of the crop. M. usitatus demonstrated to have variable lifespan when reared on different leguminous hosts but on mung bean, an important pulse crop in Bangladesh, is unknown. The experiment was conducted to determine the biological attributes of M. usitatus on mung bean in a climate control chamber at 26 ± 1°C, 75 ± 3% RH, and 16:8 hours L:D in the laboratory. The results revealed that the incubation period, first instar larva, second instar larva, prepupa, and pupal period of M. usitatus were 3.13 ± 0.06, 1.48 ± 0.05, 2.30 ± 0.08, 1.30 ± 0.07, and 2.26 ± 0.13 days, respectively. The combined developmental period from egg to adult was 10.54 ± 0.15 (mean ± SE) days. The larvae of M. usitatus were similar in appearance to the adults, but they lacked wings and were smaller and different in color. The first instar was pale yellow, while the second instar was darker and larger, ranging from deep yellow to orange-red. The wing pads of the prepupae were shorter than that of the pupae. The antennae of the prepupa were straight, but they were bent in the pupa. In the case of pre-adult mortality of M. usitatus, the mortality of the first instar larva was 14.41%, second instar larva 22.77%, prepupa 14.10%, and pupa 65.67%. The pre-adult mortality was 80.51% overall. Adult males had lower longevity (6.42 ± 0.44 days) than females (12.07± 1.56 days). The developmental period of M. usitatus on mung bean indicated the suitability of the leguminous crop as a potential host, as well as the need for information on the pest’s various growth stages in order to design effective management strategies.

Evaluation of the Effect of Different Concentrations of Spirotetramat on the Diaspine Scale Parlatoria ziziphi in Citrus Orchards

The control of Parlatoria ziziphi (Lucas, 1853) was studied in citrus orchards at Mechraa Belksiri in the Gharb area of Morocco. Three concentrations of spirotetramat T0 = 0 L/Ha as a control experiment, T1 = 0.625 L/Ha, T2 = 0.755 L/Ha, and T3 = 1 L/Ha, were applied on 4 ha of Valencia late orchard (each dose for 1 ha of Valencia late). The effect of spirotetramat was evaluated on the mortalities and survival rates of P. ziziphin during the stages of larvae (first instar and second instar) and females (F1, F2, and F3). Results showed that the spirotetramat was effective on larvae and females of P. ziziphi. Among the 11,229 females recorded, 93% were inhibited, while only 7% were intact after the treatment period. Finally, our study highlights that all concentrations tested were effective on the P. ziziphi population; besides, all three concentrations of this product tested were equally effective on larvae and females of P. ziziphi. Thus, during the spread period, spraying a low concentration of this product (0.625 L/Ha) will better control this pest and reduce the environmental impact.

How the seed coat affects the mother’s oviposition preference and larval performance in the bean beetle (Acanthoscelides obtectus, Coleoptera: Chrysomelidae, Bruchinae) in leguminous species

Background The host specificity and host range of the dry bean beetle, Acanthoscelides obtectus (Coleoptera: Chrysomelidae, Bruchinae), a seed predator of beans, is poorly known. In addition, the female oviposition preference and larval performance relationship is complicated by the respective importance of seed coat and cotyledon, because, paradoxically, females lay eggs on the basis of stimuli of the seed coat alone, without directly being able to assess the quality of the cotyledon’s suitability for larval development. Conversely, the thickness of seed coat may prevent first instar larvae from entering the seeds, even if cotyledons are suitable for development. Methods The seeds of 62 leguminous species and 75 cultivars and accessions occurring in Hungary were evaluated for preference-performance relations. The preference of female bean beetles for seeds was measured in no-choice egg-laying tests. The ability of first instar larvae to overcome the seed coat as a physical barrier was tested with intact seed coat, while pre-drilled seed coats allowed the larvae to assess the suitability of cotyledon for development. The number of emerging adults was recorded. The thickness of seed coats and the weight of seeds were measured. Nonparametric tests and logistic regression were used for the statistical analyses of data and effect sizes were also calculated. Results Seeds of 18 leguminous species (35% of them Lathyrus) supported larval development to adults if the seed coat was pre-drilled; however, only nine leguminous species supported development to adults if the seed coat was intact. Seed coat thickness beyond a critical threshold of 0.1 mm strongly influenced survival of first instar larvae. There was no overall positive correlation between oviposition preference and larval performance, except for 16 so-called acceptable non-hosts (Kendall’s τ = 0.3088). A. obtectus females also showed an ovipositional hierarchy of legume species even in no-choice tests. Conclusions The results suggest that whereas the use of some acceptable non-host species by the A. obtectus is possible in seed stores, the same is unlikely under outdoor conditions, where the recognition of a diverse set of seed pod-related compounds would be necessary to induce egg-laying.