Several arguments have been put forward to explain how sexual selection drives the evolution of sexual trait allometry, especially hyperallometry. The ‘positive allometry theory’ suggests that hyperallometry is a rule in all-secondary sexual traits, whereas the ‘display hypothesis’ suggests that only males in good condition will exhibit hyperallometric sexual display traits. In the present study, we investigated: (1) the condition-dependence nature (by using two diet treatments that varied in the amount of food provided to the larvae) of a sexually selected trait (wing pigmentation; WP) in recently-emerged adults of the American rubyspot damselfly, Hetaerina americana, and (2) the scaling relationship between WP and body size (wing and body length) in the rubyspot damselflies H. americana and Hetaerina vulnerata, according to alternative reproductive tactics (ARTs; territorial and nonterritorial males). First, we found support that indicated that diet positively affected WP length, although there was no significant WP allometric pattern in relation to diet regimes. Second, WP was hyperallometric in both Hetaerina species. WP size was similar between ARTs and, in H. americana (but not H. vulnerata), nonterritorial males showed steeper slopes than territorial males when wing length was used. The results obtained support the notion that sexual traits are hyperallometric, although there is no clear pattern in relation to ARTs.

White grubs of several species are known to plague crops such as amaranth. White grubs of the subfamily Melolonthinae significantly damage amaranth production. Agroecology theory suggests that natural fence rows provide food and cover for wildlife and help control soil erosion, which could help control plagues. However, there is no information regarding larvae and adults associated with amaranth crops in relation to natural fences. Here we record adults and larvae of Scarabaeoidea associated with Amaranthus hypochondriacus L. crop, adjacent to a deciduous forest and living fences. Results showed the occurrence of 12 species grouped in two families and seven genera. Phyllophaga obsoleta and P. ravida were the most abundant species. Larvae were collected in the growing area near the fence and in the natural zone.

La madurez de las cubiertas vegetales aumenta la presencia de enemigos naturales y la resiliencia de la red trófica de la copa del olivo