Performance of the slug parasitic nematode <i>Phasmarhabditis hermaphrodita</i> under predicted conditions of winter warming

Abstract

The nematode Phasmarhabditis hermaphrodita is the only commercial biological control agent for terrestrial slugs. We investigated whether the predicted conditions of winter warming could have any effect on its performance. In the presence of nematodes, slug damage to lettuce plants and slug survival were significantly lower under the predicted conditions of winter warming than under normal winter conditions, while in the absence of nematodes, slug damage and survival were similar under the conditions of winter warming and under current winter conditions. The data suggest that P. hermaphrodita may perform better under the predicted conditions of winter warming.

Climate change alters slug abundance but not herbivory in a temperate grassland

“…However, it is important to note that there was a significant effect of slug herbivory in the heated plots during the spring of 2013 when the differences in plant community and forage quality were minimal (unpublished data), suggesting that climate treatments were also directly influencing slug activity. Increasing temperatures have been reported to increase the herbivory of D. reticulum by reducing the presence of D. reticulum's nematode parasite, Phasmarhabditis hermaphrodita [51]. Phasmarhabditis hermaphrodita is not common in the United States, but it is possible that temperature impacts on slug predator species could result in changes in slug herbivory patterns, such as that found in this study.…”

Morph‐dependent nematode infection and its association with host movement in the land snail Cepaea nemoralis (Mollusca, Gastropoda)

“…Second, even if nematode communities are similar, conditions favourable to nematode activity, development, or infection may be reached only later in the year in the shaded habitat. For instance, Deroceras reticulatum slugs were more negatively impacted by Phasmarhabditis hermaphrodita infection when conditions were artificially warmed during winter (El‐Danasoury & Iglesias‐Piñeiro, 2017), indicating that warmer conditions may favour nematode activity. In any case, these results mean that any between‐population differences in snail behaviour in the present study should be interpreted not only in relation to microhabitat and microclimate differences but also in terms of average infection levels.…”

Morph-dependent nematode infection and its association with host movement in the land snail Cepaea nemoralis (Mollusca, Gastropoda)

“…In addition, snail morphs differ in their thermal responses: lighter-coloured morphs are better adapted to heat, and increase in frequency with global warming or urbanization (Jones et al ., 1977; Silvertown et al ., 2011; Ożgo et al ., 2017; Kerstes et al ., 2019). If lighter morphs are more vulnerable to infection by nematodes, then we need to understand how snail immunity will interact with thermal tolerances to jointly shape snail and nematode dynamics (El-Danasoury & Iglesias-Piñeiro, 2017; Aleuy & Kutz, 2020), especially given potential risks to public and veterinary health (Meerburg et al ., 2009; Giannelli et al ., 2016).…”

“…Second, even if nematode communities are similar, conditions favourable to nematode activity, development or infection may be reached only later in the year in the shaded habitat. For instance, Deroceras reticulatum slugs were more negatively impacted by Phasmarhabditis hermaphrodita infection when conditions were artificially warmed during winter (El-Danasoury & Iglesias-Piñeiro, 2017), indicating that warmer conditions may favour nematode activity. In any case, these results mean that any between-population differences in snail behaviour in the present study need to be interpreted not only in relation with microhabitat and microclimate differences, but also in terms of average infection levels.…”