Post-reproductive parthenogenetic pea aphids (Acyrthosiphon pisum) are visually identifiable and disproportionately positioned distally to clonal colonies

Abstract

The role of kin-selection in the evolution of post-reproductive life is controversial. While anthropological and demographic studies strongly suggest that humans and a few other species experience kin selection for significant post-reproductive survival, these results are necessarily correlational. Understanding could therefore be advanced by the development of a globally available, field and laboratory tractable experimental model of kin-selected post-reproductive survival. In only one invertebrate (Quadrartus yoshinomiyai, a gall-forming aphid endemic to Japan) have individuals too old to reproduce been shown to be both numerous in natural habitats and able to help close relatives survive or reproduce. Pea aphids, (Acyrthosiphon pisum), common, tractable organisms, frequently outlive their reproductive ages in laboratories, live in tight interacting groups that are often clonal, and therefore should be evaluated as potential model organisms for the study of adaptive post-reproductive life. The first major step in this process is to identify an optimal method for assessing if a parthenogenetic adult is post-reproductive. We evaluated three methods, relying respectively on isolation in clip cages, visual examination for embryonic eyespots, and dissection. In every case each method identified the same individuals as reproductive versus post-reproductive. While the clip-cage method requires a multi-day wait to produce data, and dissection is inevitably fatal, the eyespot method is quick (under one minute per individual) easy, and non-invasive. This method makes it possible to accurately assess the post-reproductive status of a large number of parthenogenetic pea aphids. We demonstrate the usefulness of the eyespot method in showing that while reproductively valuable adults tend to place themselves near the centers of clonal colonies, less valuable post-reproductive adults are more often at or beyond the edges of colonies. These encouraging early results provide both impetuous and aid for further investigations into the post-reproductive lives of pea aphids.

Chili pepper genotypes assay approach for resistance to Aphis gossypii (Hemiptera: Aphididae)

“…The clip cage could be an appropriate screening method to evaluate chili peppers resistance to aphids because it combines a detached leaf and the whole plant assay, and thus avoiding other tests which require more space, time, and energy consumed. Many researchers have used clip cage tests over the years in antibiosis-based resistance to aphid infestation (Blua and Perring, 1992;Saberski et al, 2016;Rasool et al, 2017;Sun et al, 2020). Clip cages potentially reduced the damage to the plant and are perfectly used in the laboratory, glasshouse, and in the open field (Haas et al, 2018).…”

“…Several test methods have been described for identification of insect pests infestation in the host species plants including: whole plant (Klingler et al, 2005;Michel et al, 2010;da-Costa et al, 2011), detached leaf (Michel et al, 2010;Daryanto et al, 2017), leaf disc (Maharijaya et al, 2011), and clip cage (Firdaus et al, 2012;Saberski et al, 2016;Rasool et al, 2017;Sun et al, 2020). The screening methods should be easy to conduct, generate accurate results, reproducible, time-efficient, and requiring little space to be used in the breeding program.…”