Does geographical isolation influence group recognition and social preference in an invasive lizard?

Abstract

The formation of aggregations is fundamental to animal organization and has been shown to confer an evolutionary advantage. Conspecific attraction often prompts the formation of social groups yet not all individuals are equally attracted to others of their own species. The decision to aggregate with or avoid a particular individual is based upon class‐specific signals that serve to differentiate among members and non‐members. Given that signal divergence may be driven by local adaptation, disjunct populations could potentially have evolved distinct recognition systems adapted to their own ecological conditions. Several studies have shown that individuals of a species are capable of discriminating between such classes as sex, mate, kin, and familiar. Yet research exploring conspecific attraction between populations is lacking. Invasive species offer a unique opportunity to determine the consequences of geographic isolation on recognition systems and social preferences, as these genetically distinct native‐range source populations have the potential to undergo secondary contact within the invaded region. To this end, we used an invasive lizard species, the delicate skink (Lampropholis delicata), to investigate conspecific recognition and attraction among individuals from two identified source populations that vary both genetically and morphologically. Our results of the dichotomous choice tests indicate that L. delicata did not differ in the level of social attraction expressed towards individuals from either population. It is unclear whether these findings are due to an inability to discriminate between local and foreign lizards using visual cues or instead that attraction is not based upon an individual's population origin but rather some other factor such as thermoregulatory requirements. Understanding the role that conspecific attraction plays in the invasion process will enable us to better predict the impacts of biological invasions. Future studies should consider using other sensory modalities and investigate the physiological benefit of grouping.

Temporal repeatability of behaviour in a lizard: implications for behavioural syndrome studies

“…Here, we used 57 adult male delicate skinks (Lampropholis delicata) to evaluate the stability of consistent among-individual differences in behaviour, as well as syndrome structures, across short (four weeks) and long (five months) timeframes. Consistent amongindividual variation in behavioural traits as well as their correlation has already been extensively studied in this species, where individuals were found to exhibit a well-characterized activity-exploration syndrome (Michelangeli et al 2016a(Michelangeli et al ,b, 2018(Michelangeli et al , 2019(Michelangeli et al , 2020Moule et al 2016;Goulet et al 2017a,b;Chung et al 2017), which has been linked to its success as an invasive species (Chapple et al 2011(Chapple et al , 2012(Chapple et al , 2022Chapple and Wong 2016;Hamilton et al 2020) and urban adapter (Moule et al 2016;Kang et al 2018;Walsh et al 2018). Despite the extent of this research, measurements were limited to two datapoints per individual taken over short time frames [three days to two weeks (Michelangeli et al 2016a(Michelangeli et al , b, 2018(Michelangeli et al , 2019(Michelangeli et al , 2020Moule et al 2016;Goulet et al 2017a,b;Chung et al 2017)].…”

“…As a gregarious species (e.g. Hamilton et al 2020;Littlewood et al 2021), lizards were housed in groups of six individuals within a temperature-controlled animal housing facility at Monash University (Clayton, Victoria, Australia). The room was maintained at 20 °C with a 14 h light: 10 h dark cycle (0600-2000 h).…”