Lepidoptera genitalia

About: Lepidoptera genitalia is a research topic. Over the lifetime, 10114 publications have been published within this topic receiving 78876 citations. The topic is also known as: Uncus.

Lepidopteran insect species-specific, broad-spectrum, and systemic RNA interference by spraying dsRNA on larvae

Abstract: To investigate whether the dsRNA of a gene has species-specific, broad-spectrum, or off-target effects on lepidopteran insects, we identified a methionine-rich storage protein gene (OfSP) from Asian corn borer, Ostrinia furnacalis (Guenee) (Lepidoptera: Pyralidae), using high-throughput sequence technology. The OfSP gene possesses three functional domains (N, M, and C), which are predominantly expressed in the last instars of Asian corn borer. This gene is also a key element for insect development and reproduction. The dsRNAs for the three functional domains of the OfSP gene were synthesized and sprayed on either Asian corn borer or on cotton bollworm, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), during the first instar. The dsRNA targeting the C-terminal domain can cause high mortality rates in both insects, whereas those targeting the M- and N-terminal domains only cause high mortality in the Asian corn borer. These results can be used to develop dsRNA with species-specific or broad-spectrum bio-insecticidal properties. More importantly, after dsRNA spraying, we also found typical systemic RNAi in the phenotypes that resulted in abnormal ecdysis of the larvae and pupae. Moreover, sterile eggs were found in the next generation. To analyze the broad-spectrum link to dsRNA off-target effects, the whole transcriptome siRNA libraries for these two species were constructed. Results further confirmed that 21 nucleotide siRNAs are unlikely to produce the off-target effect if conserved genes are not selected. These findings provide direct evidence confirming that dsRNA is a biologically safe insecticide in lepidopteran insect pest control.

Local pattern of host plant utilization by lepidopteran larvae in the cerrado vegetation

Abstract: DINIZ IR, MORAIS HC 2002 Local pattern of host plant utilization by lepidopteran larvae in the cerrado vegetation Entomotropica 17(2):115-119 The first inventory of lepidopteran larvae associated to buds, flowers and fruits and the study of the degree of specialization on host plant species and/or plant tissues was conducted in cerrado areas (savanna like vegetation) in Federal District (Brazil) Adults of 83 species from 15 lepidopteran families were obtained on 36 plant species of 20 families Four of the Lepidoptera families were the richest in species and included 69% of the total species: Gelechiidae (22 species), Tortricidae (17), Lycaenidae (10), and Pyralidae (8) The present results indicate three lepidopteran groups: (1) monophagous or oligophagous of a plant part from a single plant genus, 58% of the species; (2) polyphagous of plant families and plant tissues, 25% of the species; (3) oligophagous, but opportunists over the parts of the same plant species, 17% of the species

Mating delay effect on moths' reproduction: Correlation between reproduction success and calling activity in females Ephestia kuehniella, Cydia pomonella, Yponomeuta cognagellus (Lepidoptera: Pyralidae, Tortricidae, Yponomeutidae)

Abstract: The reproduction dependence in three species of moths (Ephestia kuehniella Zll., Cydia pomonella L. and Yponomeuta cognagellus Hbn.) on their age when mated has been studied. It has been established that the reproduction of females is maximal when E. kuehniella moths mate on the day of their emergence from pupa (one female lays ca 264±10 eggs, with 52±4% fertile), C. pomonella moths mate at the age of three days (one female lays ca 116±18 eggs ,with 62±8% fertile), Y. cognagellus moths mate at the age of 3-7 days (one female lays on average from 4 to 5 clutches, containing from 6 to 74 eggs each, and nearly 100% fertile). The female reproduction decreases when moths mate at different age. It has been established by means of the linear regression equation that reproduction decreases by half when mating is delayed: 3.1 days for E. kuehniella (average longevity of a virgin female is 10.5±0.3, whereas that of the female mated at its optimal age is 5.1±0.2 days), 2.9 days for C. pomonella (longevity of mated and virgin female did not differ significantly), 18.3 days for Y. 170 not at the optimal age, both the number of eggs laid and their fertility percentage decrease (the latter does not change for Y. cognagellus only). It has been demonstrated on the example of C. pomonella that changes in reproduction are determined to a great extent by the age of males. Delayed mating increased the longevity in females of all the species studied by 1.1-2.2 times. The correlation between the number of fertile eggs laid by moths mated at different age and the " calling " activity of females of a corresponding age is very strong. For E. kuehniella and C. pomonella this correlation is close to the functional dependence (r > 0.96). The conclusions are as follows: the age dynamics of the female " calling " behavior is adaptive and fully reflects the change in their reproductive potential; delayed mating inhibits the reproduction in those species of moths which lay the greatest portion of their eggs within the first day after eclosion from pupa and which demonstrate pheromone releasing behavior most actively at that age.

Risk of Infection by the Fungal Pathogen Entomophaga maimaiga Among Lepidoptera on the Forest Floor

Abstract: The entomopathogenic fungus Entomophaga maimaiga causes epizootics in gypsy moth, Lymantria dispar (L.), populations and persists in forests as a reservoir of spores in soil at the bases of trees. To investigate whether E. maimaiga infects Lepidoptera living in leaf litter, we collected and reared larvae in leaf litter, understory vegetation, and on tree boles within a 200-cm radius around trunks of red oak, Quercus rubra L., trees. Among the 358 lepidopteran larvae reared, only one gelechiid larva (out of 84 collected) and one larva of the noctuid Sunira bicolorago (out of 20 individuals from this species) were infected by E. maimaiga. Our collections included 67 gypsy moth larvae, of which 25 (37%) were infected by E. maimaiga. The majority of infected gypsy moth larvae were collected during the second half of June, when few nontarget Lepidoptera were present in the oak leaf litter. A bioassay of Zanclognatha laevigata Grote, a herminiine noctuid whose larvae spend their entire lives in leaf litter, yielded no infection. Because laboratory host specificity studies had demonstrated high levels of infection only in lymantriid larvae, we also caged larvae of the lymantriid Orgyia leucostigma (J. E. Smith) over soil at the bases of trees or in understory vegetation. Levels of infection for O. leucostigma remained consistently lower than among caged gypsy moth larvae, and infection was always higher in the soil than on the understory vegetation. We conclude that, aside from gypsy moth larvae, E. maimaiga infections among litter-dwelling lepidopteran larvae were rare, and we hypothesize that infection of other lymantriids in the field will depend on whether they visit the ground level for a significant period of time.