Hybridization between Helicoverpa armigera and Helicoverpa assulta (Lepidoptera: Noctuidae): development and morphological characterization of F₁ hybrids

Abstract

Reciprocal hybridizations between Helicoverpa armigera (Hü bner) and Helicoverpa assulta (Guenée) were studied. The cross between females of H. armigera and males of H. assulta yielded only fertile males and sterile individuals lacking an aedeagus, valva or ostium bursae. A total of 492 larvae of the F 1 generation were obtained and 374 of these completed larval development and pupated. Only 203 pupae were morphologically normal males, the remaining 171 pupae were malformed. Larvae and pupae that gave rise to morphologically abnormal adults exhibited longer development times. Sterility was not only associated with malformed external sex organs, but also a range of abnormalities of the internal reproductive system: (i) loss of internal reproductive organs, (ii) with one to three copies of an undeveloped bursa copulatrix; or (iii) with one or two undeveloped testes. Normal male hybrid adults showed higher flight activity in comparison with males of both species. In contrast, the cross between females of H. assulta and males of H. armigera yielded morphologically normal offspring (80 males and 83 females). The interaction of the Z-chromosome from H. assulta with autosomes from H. armigera might result in morphological abnormalities found in hybrids and backcrosses, and maternal-zygotic incompatibilities might contribute to sex bias attributed to hybrid inviability.

Evidence of potential hybridization in the Thaumetopoea pityocampa‐wilkinsoni complex

“…Hybrid zones are common in insects (Zhao et al ., ; Mallet et al ., ; Descimon & Mallet, ; Gompert et al ., ) and can entail complex interactions between the species (Hewitt, ; Bridle & Vines, ). In the winter pine processionary moth complex, the occurrence of hybrid zones has been hypothesized by Kerdelhué et al .…”

Sensillar expression and responses of olfactory receptors reveal different peripheral coding in two Helicoverpa species using the same pheromone components

“…The two species are morphologically similar and share the same sex pheromone components 13 . Interspecific hybridization had been accomplished in the lab, producing in some cases viable offspring 14 15 . The two main components of their sex pheromones are ( Z )-11-hexadecenal (Z11-16:Ald) and ( Z )-9-hexadecenal (Z9-16:Ald), used by the two species in nearly reversed ratios, 100:2 by H. armigera and 6:100 by H. assulta , thus ensuring segregation in nature 16 17 .…”

Mitochondrial DNA genomes of five majorHelicoverpapest species from the Old and New Worlds (Lepidoptera: Noctuidae)

“…The incorrectly reported H. assulta mitogenome (Li et al, ) may have arisen as a result of hybridization between a female H. armigera and a male H. assulta which may have appeared morphologically similar to H. assulta . Hybrids resulting from mating between H. armigera and H. assulta are known to occur under experimental conditions (e.g., Wang, Zhao, & Wang, ; Zhao et al, ), though there has been no molecular investigation of the nature of the hybridization. The individual collected and sequenced by Li et al () originated from a cotton field which is unusual for a Solanaceae specialist such as H. assulta (Ahn, Badenes‐Perez, & Heckel, ), though H. assulta from cotton fields in Australia has occasionally also been reported (Sharon Downes and Mary Whitehouse CSIRO, pers.…”