The high invasion success of fall armyworm is related to life-history strategies across a range of stressful temperatures

A neurotransmitter histamine mediating phototransduction and photopreference in Callosobruchus maculatus

BACKGROUND

The biogenic amine histamine plays a critical role in the phototransduction and photopreference of most insects. Here, we study the function of histamine in Callosobruchus maculatus, a global storage pest.

RESULTS

In our experiment, we initially identified the histidine decarboxylase (hdc) gene through bioinformation analysis. We subsequently investigated effects of hdc and histamine on the photopreference of C. maculatus using a combination of RNA interference (RNAi), electroretinograms (ERG), immunostaining, and photopreference behavior approaches. Our results showed that histamine was required for visual signal transduction of C. maculatus, and increased its photopreference regardless of the wavelength.

CONCLUSION

This is the first study analyzing the molecular characteristics of C. maculatus photopreference, which forms the basis for a molecular mechanism for the effects of histamine on its visual transduction and preference. In practice, better understanding the photopreference patterns contributes to IPM (integrated pest management) for this storage pest. © 2023 Society of Chemical Industry.

Fall armyworm from a maize multi-peril pest risk perspective

We assembled 3,175 geo-tagged occurrences of fall armyworm worldwide and used that data in conjunction with information about the physiological requirements of the pest to spatially assess its global climate suitability. Our analysis indicates that almost the entire African maize crop is grown in areas with climates that support seasonal infestations of the insect, while almost 92% of the maize area supports year-round growth of the pest. In contrast, rich-country maize production largely occurs in temperate areas where only 2.3% of the area may allow the pest to survive year-round, although still subject to worrisome seasonal risks. This means the African maize crop is especially susceptible to damaging infestation from fall armyworm, on par with the risk exposure to this pest faced by maize producers throughout Latin America. We show that the maize grown in Africa is also especially vulnerable to infestations from a host of other crop pests. Our multi-peril pest risk study reveals that over 95% of the African maize area deemed climate suitable for fall armyworm, can also support year-round survival of at least three or more pests. The spatial concurrence of climatically suitable locations for these pests raises the production risk for farmers well above the risks posed from fall armyworm alone. Starkly, over half (52.5%) of the African maize area deemed suitable for fall armyworm is also at risk from a further nine pests, while over a third (38.1%) of the area is susceptible to an additional 10 pests. This constitutes an exceptionally risky production environment for African maize producers, with substantive and complex implications for developing and implementing crop breeding, biological, chemical and other crop management strategies to help mitigate these multi-peril risks.

Positive Interactions between Aceria pallida and Bactericera gobica on Goji Berry Plants

The gall mite Aceria pallida and the psyllid Bactericera gobica are serious Goji berry pests. The mite can be phoretic on the psyllid to overwinter, but it is unclear whether the vector can obtain benefits from the phoront during the growing season. After detachment, the mite shares the same habitat with its vector, so there are very likely to be interspecific interactions. To better understand whether the interactions are positive or negative, information on relationships between abundances of A. pallida and B. gobica on leaves is needed. Here, B. gobica abundance was represented by the egg abundance because the inactive nymphs develop on the same sites after hatching. (1) We found a positive linear relationship between the gall diameter and the mite abundance in the gall (one more millimeter on gall diameter for every 30 mites increase), which provided a way to rapidly estimate mite abundances in the field by measuring gall diameters. (2) There was a positive relationship between the abundance of mites and psyllid eggs on leaves. (3) Both species had positive effects on each other’s habitat selections. More importantly, the interactions of the two species prevented leaf abscission induced by B. gobica (leaf lifespan increased by 62.9%), increasing the continuation of the psyllid population. Our study suggests positive interactions between two pests during the growing season. The positive relationship between A. pallida and B. gobica egg abundances highlights the increasing need for novel methods for Goji berry pest management. In practice, A. pallida control can be efficient by eliminating its vector B. gobica. Both pests can be controlled together, which reduces chemical usage.