Melanism and disease resistance in insects

By K. Wilson, S. Cotter, Andrew F Reeson, J. Pell. 2001

465 citations recorded by the source corpus.

There is growing evidence that insects in high-density populations invest relatively more in pathogen resistance than those in low-density populations (i.e. density-dependent prophylaxis). Such increases in resistance are often accompanied by cuticular melanism, which is characteristic of the high-density form of many phase polyphenic insects. Both melanism and pathogen resistance involve the prophenoloxidase enzyme system. In this paper the link between resistance, melanism and phenoloxidase activity is examined in Spodoptera larvae. In S. exempta, cuticular melanism was positively correlated with phenoloxidase activity in the cuticle, haemolymph and midgut. Melanic S. exempta larvae were found to melanize a greater proportion of eggs of the ectoparasitoid Euplectrus laphygmae than non-melanic larvae, and melanic S. littoralis were more resistant to the entomopathogenic fungus Beauveria bassiana (in S. exempta the association between melanism and fungal resistance was non-signficant). These results strengthen the link between melanism and disease resistance and implicate the involvement of phenoloxidase.

Subfields: Genetics, Insect Science

View Paper: https://www.semanticscholar.org/paper/82a0672d2462237d31b6591ccf8d8e9bff7c6618

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Citations in the corpus

Dissolved humic substances – ecological driving forces from the individual to the ecosystem level? (2006, background): “similar to the response of many invertebrates to parasite infections: development of a kind of oxidative stress (Wilson et al., 2001; Mucklow et al., 2004; Newton, Peters & Raftos, 2004).”
Phenoloxidase: a key component of the insect immune system (2012, background): “…Animals kept under crowded conditions showed higher PO values in hemolymph, midgut, and cuticle compared to animals kept in solitary conditions Wilson et al. (2001) Daphnia magna Nutritional status Positive Well-fed Daphnia showed higher PO activity than Daphnia kept at a low food level…”
Density-dependent prophylaxis and condition-dependent immune function in Lepidopteran larvae: a multivariate approach (2004, background): “…of the basis for the increased resistance to parasites and pathogens of melanic, gregaria phase larvae reported in a number of previous studies (Mitsui & Kunimi 1988; Kunimi & Yamada 1990; Hochberg 1991; Goulson & Cory 1995; Reeson et al. 1998; Barnes & Siva-Jothy 2000; Wilson et al. 2001).”
Variation in thermally induced melanism in monarch butterflies (Lepidoptera: Nymphalidae) from three North American populations (2005, background): “Because immune function has been shown to correlate positively with increased melanization and body coloration in other insect species (Wilson et al., 2001), future experiments should examine the relationships between melanism, temperature, and parasite infection in this system.”
The lizard Psammodromus algirus (Squamata: Lacertidae) is darker at high altitudes (2014, background): “Second, melanin has been related to improved immunocompetence and higher resistance against parasites and pathogens in different taxa (Wilson et al., 2001; Burtt & Ichida, 2004; Moreno & Møller, 2006).”
What, if anything, is the adaptive function of countershading? (2004, background): “Fitze & Richner 2002) and in antiparasite defences (e.g. discussions and data in Mackintosh 2001; Wilson et al. 2001).”
Group living and investment in immune defence: an interspecific analysis (2003, background): “Moreover, across three phenotypes of S. exempta larvae, there was a positive correlation between PO activity and baculovirus LD50 (Reeson et al. 1998; Wilson et al. 2001 ).”
Mixed infections and insect–pathogen interactions (2003, unknown): “…phagocytosis of foreign bodies such as fungal blastospores (Bidochka et al. 1997) and it is possible that the level of haemocyte activity, together with other non-specific elements of the immune response (see Gillespie et al. 1997; Wilson et al. 2001), are enhanced under multiple disease challenge.”
Natural host‐plant quality affects immune defence of an insect herbivore (2007, background): “…low-quality trees as typical of crowded conditions and prepared themselves to sustain increased parasitism and the transfer of pathogens and diseases at high densities (i.e., the hypothesis of densitydependent prophylaxis) (Wilson & Reeson, 1998; Wilson et al., 2001; see also Kapari et al., 2006).”
The antioxidant function of many animal pigments: are there consistent health benefits of sexually selected colourants? (2005, background): “Heavily melanized lepidopterans more effectively resist parasitoid colonization and viral and fungal infections (reviewed in Wilson et al. 2001).”
Challenges in modelling complexity of fungal entomopathogens in semi-natural populations of insects (2009, background): “However, few studies show that host investment in resistance to fungal entomopathogens may change depending upon host density and these are limited to species exhibiting density-dependent phase polyphenism (Wilson et al. 2001, 2002).”
Action on the Surface: Entomopathogenic Fungi versus the Insect Cuticle (2013, background): “fungal susceptibility and melanism was seen, indicating the complex nature of the interaction between microbial pathogens and host defenses and the variability in outcomes that can occur [63].”