The effect of Rickia wasmannii (Ascomycota, Laboulbeniales) on the aggression and boldness of Myrmica scabrinodis (Hymenoptera, Formicidae)

Abstract

The interactions of ectosymbiotic Laboulbeniales (Ascomycota) fungi and their hosts are rather understudied. Rickia wasmannii Cavara is a common ant-associated Laboulbeniales species that has been reported in 17 countries of Europe, and frequently infects Myrmica scabrinodis Nylander, 1846 (Hymenoptera: Formicidae), a common ant species host, in high density. These make M. scabrinodis and R. wasmannii appropriate model organisms for studies on fungal host-ectosymbiont interactions. Aggressiveness and boldness of infected and uninfected M. scabrinodis workers from northern and eastern Hungary were studied in two laboratory-established behavioural experiments. Infected workers were significantly less aggressive and less bold (i.e. less likely to leave nest shelters) than the uninfected ones. These results suggest that R. wasmannii has considerable effects on the behaviour of M. scabrinodis. Our study brings an evidence that infection of ants with Laboulbeniales might negatively affect the workers' behaviour. In special, the competitive abilities might be affected most by these fungi, since remaining inside and behaving submissively is not effective behaviour in the case of significant competition for resources among colonies.

New species of Troglomyces and Diplopodomyces (Laboulbeniales, Ascomycota) from millipedes (Diplopoda)

“…It is a common view that these fungi have little or no effect on their hosts (Benjamin 1971;Tavares 1985). Fitness effects have been estimated by a few controlled studies (Whisler 1968;Strandberg & Tucker 1974), as well as some insights into how these fungi may influence the behaviour of their hosts (Konrad et al 2014;Báthori et al 2017;Csata et al 2017). Their source of nutrients is debatable, but they are believed to draw them from their hosts through absorption or via contact with living tissues (Scheloske 1969;Benjamin 1971;Tavares 1985).…”

Entomopathogenic Rickia wasmannii fungal infection generated colony-level stress effects cause size decline in Myrmica ants

“…Earlier, laboratory based findings and field studies have shown that this fungal infection does not attack Myrmica larvae [11,21,24,25] , but is known to cause an array of detrimental changes in physiology in individual ant workers, such as a decrease in life expectancy, particularly in cases of water and food deprivation [15] , increased sanitary behavior [14] , and a reduced ability to fight against competitors [16,17] . Yet, despite the number of negative effects detected under laboratory conditions, infected colonies in the field have been thought to function relatively well, as they contain queens, larvae and pupae, and all age-classes of workers (see Csata et al [17] ).…”

“…Based on previous studies on the physiological response of infected workers of the main host Myrmica scabrinodis Nylander, 1846, infected workers show higher mortality under laboratory conditions [14,15] . Infected M. scabrinodis workers were also shown to exhibit improved sanitary behavior [14] and a decreased level of intraspecific aggressivity [16,17] which may be disadvantageous for the infected colonies in competitive interactions.…”

Host Ant Change of a Socially Parasitic Butterfly (Phengaris alcon) through Host Nest Take-Over

“…It is a well-known phenomenon that ants avoid or attack individuals from foreign colonies, whether of the same or a different species [ 2 , 28 ], which we have also experienced often with Myrmica ants in the lab [ 29 , 30 ]. Whether aggression takes place, and how strong it is, depends on multiple factors, including resource availability [ 31 , 32 ], territory or nest ownership [ 33 , 34 , 35 ], the presence of social and individual parasites [ 29 , 30 ], and recognition of intruders as being “non-self” [ 34 , 36 ], primarily through colony and species-level differences in cuticular hydrocarbons (CHCs) [ 37 ]. The level of aggression is generally directly and positively related to the dissimilarity between the CHCs of the colony and the intruders [ 38 , 39 ].…”