Elevated maternal temperature enhances offspring disease resistance in Daphnia magna

Abstract

Summary1. Maternal effects are increasingly recognized to impact upon infectious diseases. Stressful environmental conditions that coincide with high infection prevalence are potential cues for adaptive maternal effects on offspring resistance to infection. 2. We studied how maternal temperature (15°C, 20°C and 25°C), as well as maternal food availability (high and low food) influenced the ability of the crustacean, Daphnia magna, to resist its bacterial parasite, Pasteuria ramosa. 3. Mothers held at a higher temperature and mothers fed a restricted diet produced offspring that were more resistant to P. ramosa infection. 4. Maternal temperature also influenced the progression of disease in infected offspring. Parasite spore production and host reproduction were affected by maternal temperature, but these effects differed in the two genotypes used. 5. As Daphnia populations experience regular summer epidemics of P. ramosa, temperature may be an environmental signal of infection risk. Thus, the enhanced resistance we observed under stressful food and temperature is conceivably an adaptation to looming epidemics. 6. Thus, this study identifies novel ways in which the maternal environment impacts upon disease resistance and indicates how phenotypic plasticity might both alter co-evolution and mitigate epidemics driven by environmental change in a wide range of taxa.

The development of pathogen resistance in Daphnia magna: implications for disease spread in age-structured populations

“…In particular, we show that the protective effect evident in the offspring of food-restricted mothers (Ben-Ami et al, 2010;Garbutt et al, 2014;Mitchell and Read, 2005;Stjernman and Little, 2011) persists through much of their juvenile period. That the maternal effect persists until the time that the daphnid nearly reaches reproductive maturity (the time that eggs begin to develop) highlights the potential for the effect to be transmitted one generation further (i.e.…”

“…With this in mind, it is tempting to assume that invertebrates, which possess only an innate immune system, would not show an immune system or defence ontogeny similar to that of young vertebrates. Yet, in general, the innate immune system of invertebrates is surprisingly capable, and there is even evidence that it develops through time in response to challenges from pathogens (McTaggart et al, 2012), or can be modified via maternal effects (Ben-Ami et al, 2010;Garbutt et al, 2014;Little et al, 2003;Mitchell and Read, 2005;Stjernman and Little, 2011). What has been little studied, however, is the basic ontogeny of immunity early in the life of invertebrates.…”

Maternal food quantity affects offspring feeding rate in Daphnia magna

“…To enable individual Daphnia to be treated as independent replicates, and to avoid the accumulation of uncontrolled transgenerational effects in the experimental animals, 20-24 replicate clonal lineages of each genotype were maintained under standard conditions for three generations prior to their use in experiments as previously described [13]. During this period, Daphnia received 5 Â 10 6 Chorella algae/day, which was estimated by measuring the absorbance of the algae at 664 nm white light, and which was the same as the 'high-food' treatment below.…”

Arginine kinase in the cladoceran Daphnia magna: cDNA sequencing and expression is associated with resistance to toxic Microcystis

“…6B) which could lead to enhanced resistance to toxic cyanobacteria. It has been wellaccepted that Daphnia in a poor-food environment produce small broods of large neonates (Garbutt et al, 2013), whereas daphnids in a good-food environment produce large broods of small neonates (Enserink et al, 1990;Gliwicz and Guisande, 1992;Coors et al, 2004). The large neonates contain a higher amount of lipids (Enserink et al, 1993) and are assumed to be of higher quality than small neonates.…”