The Innate Immune Response of Eusocial Hymenopterans to Viral Pathogen Challenge

In recent years, insect immunology has expanded rapidly in research interest, and available literature has expanded in kind. Insects combat pathogens through a range of behavioral and physiological immune defenses. The need for robust immunity is especially important to eusocial insects; nestmate proximity increases exposure to and transmission of pathogens. Further, eusociality involves cohabitation of thousands of individuals with characteristically reduced genetic variability, in turn increasing susceptibility to epidemic disease outbreaks. To combat this, they have developed diverse responses to pathogens, including individual innate immune defenses, social immunity, and secretion of potent glandular chemicals. The range of immune responses is as diverse as the pathogens presenting the threat, and of these, viruses may present the greatest challenge. Social immunity employed by Hymenoptera and has been reviewed whereas a review has not been developed to our knowledge addressing innate immunity of eusocial Hymenopterans to viral pathogenic invaders. We argue that such a review is important to advancement of understanding of Hymenopteran biology and is critical to applied interests. We argue further that the implications of eusocial Hymenopteran innate immunity are far-reaching; their success is a source of both substantial economic loss in the case of invasive ants and significant economic gain in the case of the honey bee Apis mellifera.