Oviposition and Development in Gregopimpla kuwanae Viereck (Hymenoptera: Ichneumonidae), a Gregarious Ectoparasitoid Wasp Attacking the Rice Skipper Parnara guttata

Gregopimpla kuwanae is a gregarious ectoparasitoid wasp attacking mature larvae and prepupae of the rice skipper Parnara guttata (Lepidoptera: Hesperiidae), a major herbivorous pest in rice paddies. Here, the biology of G. kuwanae was investigated using Galleria mellonella as a laboratory host. Adult females accepted G. mellonella cocoons for oviposition, and larvae of G. kuwanae developed successfully to adulthood on this host. Females laid, on average, 3.5 eggs per host. Time required for oviposition was relatively long (mean = 14.2 min). Survival of parasitoid offspring decreased with the increasing number of eggs on each host. Females used 18.9% of hosts for host feeding, killing the hosts with no exception. Oviposition did not occur on hosts used for feeding purpose, indicating that the parasitoid was a nonconcurrent, destructive host feeder. Newly emerging adult females carried no eggs in the ovary; females started oogenesis only after they had destructively fed on hosts. This parasitoid thus was extremely synovigenic (ovigeny index = 0). Gregopimpla kuwanae laid typically yolk-rich, anhydropic eggs. Females carried on average 15 mature eggs with 20 immature eggs, and larger females had a greater number of eggs in the ovary. Life history characteristics of G. kuwanae were discussed.

Infestation of Glycaspis brimblecombei Moore on Thirteen Eucalyptus Species and Their Relationship with the Chemical Composition of Essential Oils

Glycaspis brimblecombei is a pest insect that affects Eucalyptus genus and was firstly detected in Argentina in 2005. The main objective of this study is to determine the correlation between the level of infestation and chemical composition of essential oils extract. In an experimental plantation of 13 Eucalyptus species, the natural presence of the psyllid in the adaxial and abaxial faces of the leaves was determined and the mean number of individuals per species was calculated. The essential oils were extracted by hydrodistillation and analyzed for their chemical composition by gas chromatography-mass spectrometry. The results showed that 7 out of 13 species of Eucalyptus were not affected by G. brimblecombei: E. dunnii, E. globulus maidenii, E. globulus ssp. globulus, E. viminalis, E. cinerea, E. sideroxylon, and E. gunnii. The most affected Eucalyptus species were E. tereticornis and E. camaldulensis whereas the infestation in E. grandis × E. tereticornis and E. grandis × E. camaldulensis was intermediate. E. saligna and E. grandis were the least affected species. The relative concentrations of the compounds 1,8-cineole and α- and β-phellandrene in the essential oils are highly correlated to the rate of infestation with G. brimblecombei.

Genetic and Linkage Studies of New Autosomal Sex-Limited Mutant Hairless Antenna in Anopheles stephensi Liston

A new morphological mutant hairless antenna (hla) was induced in the mosquito Anopheles stephensi by γ-irradiation. The expression of the mutant in the male adult revealed the antennae without the hairs. The inheritance pattern from our data demonstrates that hairless antenna is essentially sex-limited to males and is autosomal and recessive. The linkage relationships studies between the hairless antenna and greyish brown larva (grb) mutant indicated independent assortment and are present on different chromosomes, while the linkage relationship studies between the hairless antenna and ruby eye (ru) mutant revealed the suppression of hla by the ru gene in heterozygous condition. These mutants can be useful in conducting basic and applied research such as construction of linkage maps and understanding biochemical pathways and in genetic control programmes.

Habitats and Foraging Movements of Larvae of Molanna uniophila Vorhies (Trichoptera: Molannidae) in Pratt Lake, Michigan, USA

Habitats and foraging movements of larvae of Molanna uniophila Vorhies (Trichoptera: Molannidae) were studied during four summers in Pratt Lake, Michigan. Larvae lived and fed in shallow (<10 cm), sand-bottomed lake margins, where macrophyte densities ranged from 86 to 452 stems/m2. Average densities of larvae varied fivefold between years (2.7 versus 13.6 individuals/m2), but larval densities did not vary significantly between habitat patches with low (120 stems/m2) and high (360 stems/m2) macrophyte densities. Larvae and their cases exhibited strong patterns of simple, linear growth. Diets of larvae were dominated by amorphous detritus, plant debris, diatoms, and filamentous algae, but midges, cladocerans, and other microscopic aquatic animals also were consumed. Larvae shifted their bodies and cases forward across the surface sediments up to 4 times/minute while foraging, moving as much as 2.5 m/hour. Movements and distances traveled while feeding increased significantly with increased water temperatures, peaking during midafternoon hours. Distances moved by feeding larvae did not differ between habitats with low versus high macrophyte densities. Larvae foraged most actively during daylight hours and did not selectively utilize macrophyte beds as partial refugia from potential predators while feeding.

Short-Term Dynamics Reveals Seasonality in a Subtropical Heliconius Butterfly

Although tropical insect populations are generally regarded as constant and stable over time, some of these tropical populations, including butterflies, may fluctuate according to precipitation and temperature variation, specialized feeding patterns, and density-dependent factors. Heliconiini butterfly populations are generally regarded as stable over time because of the presence of host-plants and absence of diapause. However, peaks of abundance occur in subtropical Heliconius populations, and opposite trends concerning stability are found in the literature. Here we further investigate the dynamics of subtropical Heliconius butterflies by assessing a population of the species Heliconius sara apseudes from southeastern Brazil. We estimated individual apparent survival probability and population growth rate while accounting for the imperfect detectability of individuals using mark-recapture models to evaluate the population dynamics. Adult males presented slightly higher weekly survival estimates than females. Contrary to the common pattern described in the literature for Heliconius populations we observed a rapid decline on the adult population by the end of the mating season, possibly leading to local extinction. We discuss the potential drivers for such dynamics.

Measuring Intraspecific Variation in Flight-Related Morphology of Monarch Butterflies (Danaus plexippus): Which Sex Has the Best Flying Gear?

Optimal flight in butterflies depends on structural features of the wings and body, including wing size, flight muscle size, and wing loading. Arguably, there is no butterfly for which flight is more important than the monarch (Danaus plexippus), which undergoes long-distance migrations in North America. We examined morphological features of monarchs that would explain the apparent higher migratory success and flight ability of females over males. We examined 47 male and 45 female monarch specimens from a project where monarchs were reared under uniform conditions. We weighed individual body parts, including the thorax (flight muscle) and wings, and computed wing loading and wing thickness for all specimens. When we compared each morphological trait between sexes, we found that females did not differ from males in terms of relative thorax (wing muscle) size. Females were generally smaller than males, but females had relatively thicker wings than males for their size, which suggests greater mechanical strength. Importantly, females had significantly lower wing loading than males (7% lower). This would translate to more efficient flight, which may explain their higher migratory success. Results of this work should be useful for interpreting flight behavior and/or migration success in this and other Lepidopteran species.

Life History of the Tamarind Weevil, Sitophilus linearis (Herbst) (Coleoptera: Curculionidae), on Tamarind Seed

The tamarind weevil, Sitophilus linearis Herbst (Coleoptera: Curculionidae), is an important pest of tamarind and other Caesalpinioideae. Investigating its life history is important in the implementation of management strategy. Its life history was monitored daily to understand its developmental biology on tamarind seed following standard procedures under laboratory conditions of 24–30°C temperature, 60–70% relative humidity, and 12L : 12D photoperiod. The egg incubation period lasted 3.17 ± 0.07 days. A mated female of S. linearis laid an average of 165 ± 5.78 eggs during an oviposition period of 86.8 ± 2.47 days. There were four larval instars, with a total larval developmental period of 16 days. The pupal period lasted 8 days, and adult lived 108.5 ± 3.61 days. The overall growth ratio for the four instars was 1.33. There was a regular relationship and significant correlation (r=0.94) between the stages of larval development and head capsule width.

Chemical Composition and Insecticidal and Repellent Effect of Essential Oils of Two Premna Species against Sitotroga cerealella

This work aims to study for the first time the chemical composition and evaluate insecticidal and repellent effects of essential oils of Premna angolensis and Premna quadrifolia leaves, against Sitotroga cerealella, an insect pest of rice stocks as alternatives to synthetic pesticides. The GC-MS analysis showed that essential oil of P. angolensis contains 29 compounds representing 96.1% of the oil and 42 compounds corresponding to 91% for the essential oil of P. quadrifolia. The main constituents regardless of the species were β-caryophyllene (13.1%), (E)-β-caryophyllene (13.5%), octen-3-ol (3.2%–28%), phytol (3.7%–4.9%), β-elemene (1.4%–21%), globulol (11.2%), germacrene-D (8.9%), α-humulene (2.9%–6.4%), α-pinene (5%), sabinene (3.7%), δ-cadinene (0.4%–3.3%), and linalool (3.3%). The results of laboratory tests showed that both essential oils have insecticidal and repellent effects on S. cerealella. Presenting the results, the damage caused by the adults and larvae of S. cerealella was evaluated by calculating the percentage of grains attacked and weight loss thereof. The results suggest that volatile extracts of P. angolensis and P. quadrifolia can be used as alternatives to synthetic chemicals in paddy protection against S. cerealella.

Insect Vectors of Rice Yellow Mottle Virus

Rice yellow mottle virus (RYMV) is the major viral constraint to rice production in Africa. RYMV was first identified in 1966 in Kenya and then later in most African countries where rice is grown. Several studies have been conducted so far on its evolution, pathogenicity, resistance genes, and especially its dissemination by insects. Many of these studies showed that, among RYMV vectors, insects especially leaf-feeders found in rice fields are the major source of virus transmission. Many studies have shown that the virus is vectored by several insect species in a process of a first ingestion of leaf material and subsequent transmission in following feedings. About forty insect species were identified as vectors of RYMV since 1970 up to now. They were essentially the beetles, grasshoppers, and the leafhoppers. For this review, we presented the chronology of their identification. Also, the biology, ecology, host range, distribution, and caused damage of these insects were briefly summarized.

Phenology of Migration and Decline in Colony Numbers and Crop Hosts of Giant Honeybee (Apis dorsata F.) in Semiarid Environment of Northwest India

The colonies of the giant honeybee (Apis dorsata) immigrate in the semiarid environment of Northwest India in October-November with the onset of flowering on pigeon pea (Cajanus cajan)/toria (Brassica campestris var. toria), stay here during the rich pollen and nectar flow period from December to mid-May, and emigrate in late May/early June when floral dearth is witnessed. This honeybee was free from any conspicuous viral, bacterial, and fungal diseases and also did not have any serious predators and enemies. However, about 20 percent of the old colonies were infested with Tropilaelaps clareae and 100 percent of the old colonies with Galleria mellonella; none of the swarm colonies had these pests. While the migration schedule of this honeybee remained similar year after year, the number of colonies immigrating in this region declined markedly over the years; the number in 2012 was even less than half of that recorded in 1984. During its stay in this region, this honeybee acted as an important pollinator of more than 30 crop plants of this region. The causes of seasonal migration and decline in the number of colonies of this honeybee and its importance in crop pollination have been discussed.