Assessing immunocompetence in red palm weevil adult and immature stages in response to bacterial challenge and entomopathogenic nematode infection

AbstractParasites and pathogens can follow different patterns of infection depending on the host developmental stage or sex. In fact, immune function is energetically costly for hosts and trade ‐offs exist between immune defenses and life history traits as growth, development and reproduction and organisms should thus optimize immune defense through their life cycle according to their developmental stage. Identifying the most susceptible target and the most virulent pathogen is particula rly important in the case of insect pests, in order to develop effective control strategies targeting the most vulnerable individuals with the most effective control agent. Here, we carried out laboratory tests to identify the most susceptible target of infection by infecting different stages of the red palm weevilRhynchophorus ferrugineus (larvae, pupae, male, and female adults) with both a generic pathogen, antibiotic ‐resistant Gram‐negative bacteriaEscherichia coli XL1 ‐Blue, and two specific strains of entomopathogenic nematodes (EPNs),Steinernema carpocapsae ItS ‐CAO1 andHeterorhabditis bacteriophora ItH ‐LU1. By evaluating bacterial clearance, host mortality and parasite progeny release, we demonstrate that larvae are more resistant than adults to bacterial challenge and they release less EPNs progeny after infection despite a higher mortality compared to adults. Considering the two EPN strains,S. carpocapsae was more virulent thanH. bacteriophora both in terms of host mort...
Source: Insect Science - Category: Biology Authors: Tags: ORIGINAL ARTICLE Source Type: research