Cristaldo, P. F. | bioRxiv Science

bioRxiv2021

Adaptations and responses of the common dandelion to low atmospheric pressure in high altitude environments

Atmospheric pressure is an important, yet understudied factor that may shape plant ecology and evolution. By growing plants under controlled conditions at different experimental stations in the Swiss alps, we evaluated the impact of ecologically realistic atmospheric pressures between 660 and 950 hPa on the growth and defence of different dandelion populations. Low atmospheric pressure was associated with reduced root growth and defensive sesquiterpene lactone production. Defense suppression only occurred in populations originating from lower altitudes. Populations from higher altitudes constitutively produced less sesquiterpene lactones and did not suffer from suppression under low atmospheric pressure. We conclude that atmospheric pressure modulates root growth and defence traits, and that evolutionary history shapes plant phenotypic responses to atmospheric pressure. Our findings have important implications for our understanding of altitudinal gradients and the future use of plants as a source of food and bioactive metabolites in extraterrestrial habitats.

plant biology↗

bioRxiv2019

Peaceful behaviour: a strategy employed by an obligate nest invader to avoid conflict with its host species

In addition to its builders, termite nests are known to house a variety of secondary, opportunistic termite species, but little is known about the mechanisms governing the maintenance of such associations. In a single nest, host and intruder are likely to engage in intense conflict, due to their nestmate discrimination system. An intriguing question is how individuals cope with such a burden in the long term. Evasive behaviour has been previously suggested as a mechanism that reduces the frequency of encounters between non-nestmates. However, due to confinement imposed by the nests physical boundaries, it is likely that hosts and inquilines would eventually come across each other. Under these circumstances, it is plausible that inquilines would be required to behave accordingly to secure their housing. Here, we tested this hypothesis predicting that, once inevitably exposed to hosts, inquiline individuals would modulate their behaviour to circumvent conflict. While exploring the behavioural dynamics of the encounter between both cohabitants, we find evidence for an unusual lack of aggressiveness by inquilines towards hosts. Such a non-aggressive behaviour is characterised by evasive manoeuvres that include reversing direction, bypassing and a defensive mechanism using defecation to repel hosts. The behavioural adaptations we describe may play an intrinsic role in the stability of cohabitations between termite species: by reducing the costs of conflicts to both cohabitants, it may improve the chances for stable nest-sharing considerably.

animal behavior and cognition↗