Do differences in bite force and head morphology between a native and an introduced species of anole influence the outcome of species interactions?

Abstract

Species invasions may drive native species to extinction. Yet, the role of competition with a closely related native species in the establishment success of an invasive species remains poorly understood. Indeed, opportunities to study native-invasive competition in action are rare, especially at the very first stages of the invasion. We studied the recent invasion of the lizard Anolis cristatellus in Dominica, where the native Anolis oculatus occurs. We examined the species difference in bite force as a proxy for fighting ability and access to food resources, and its effect on the establishment success of the invasive species. We measured head morphology and bite force of 371 and 129 adults of both species, and compared four allopatric and five sympatric populations in banana farms in an area (Calibishie) where the two species have been in contact for only a few years. This study revealed higher absolute bite forces of A. oculatus, ruling out the superior fighting ability hypothesis as a determinant for the establishment of A. cristatellus in Calibishie. The species differences in bite force and head morphology are present in allopatry and sympatry, suggesting that recent interspecific competition has no observable effect on these traits. We discuss other possible mechanisms allowing the establishment success of A. cristatellus in Dominica.

Recent biological invasion shapes species recognition and aggressive behaviour in a native species: A behavioural experiment using robots in the field

“…Anolis oculatus presents species‐specific signals (i.e. display: Dufour et al, 2018a; and morphology: Dufour et al, 2018a; Dufour et al, 2018) and recognition (this study) allowing it to discriminate between conspecifics and A. cristatellus , despite having no common history with the invasive species (Losos, 2009). This result enriches the unexpected, yet significant list of examples of allopatric species who have been demonstrated to show species recognition (Ord, King, & Young, 2011).…”

“…In Panama and Costa Rica, Pasch et al (2013) revealed that aggressive dominance mediates altitudinal zonation in two species of neotropical singing mice. In Dominica, morphological (Dufour et al, 2018a), physiological (Dufour et al, 2018) and behavioural evidence (Dufour et al, 2018b) (Anderson & Grether, 2010;Grether et al, 2017), reproductive (Höbel & Gerhardt, 2003) and exploitative (resource use ;Huber, León, Hendry, Bermingham, & Podos, 2007;Huber & Podos, 2006) competition between closely related species may drive changes in species recognition and display. Indeed, populations can respond to aggressive interspecific interference by shifting phenotypically in traits that affect the rate, intensity or outcome of interspecific aggression (Anderson & Grether, 2010;Grether et al, 2013Grether et al, , 2017Grether, Losin, Anderson, & Okamoto, 2009).…”

“…on perch height and subsequently limb morphology and toepad traits; Dufour et al, 2018a). In response to recent interspecific competition, behavioural changes appear to precede morphological and physiological changes in both species (Dufour et al, 2018a, 2018b; Dufour et al, 2018). Finally, because the spread of A. cristatellus has been patchy, allopatric and sympatric populations can be compared in similar environmental conditions (Dufour et al, 2018a, 2018b).…”

“…The two species are ecologically and morphologically similar, so much so, that several scientists predicted that the species would compete strongly (Daniells et al, 2008;Malhotra, Thorpe, Hypolite, & James, 2007). Indeed, behavioural interference and indirect competition by resource exploitation between the two species has been documented (Dufour et al, 2018a;Dufour, Herrel, & Losos, 2018b;Dufour, Losos, & Herrel, 2018) and has led to a shift in the display behaviour of the invasive species (i.e. decrease of display-time spent dewlapping; Dufour et al, 2018b) and to ecological character displacement in both species (i.e.…”

No need for artificial light: nocturnal activity by a diurnal reptile under lunar light

“…Lastly, as invasive species tend to be generalist and highly adaptive species with broad niches [26][27][28], filling seemingly untaken niches would aid invasive success and establishment. Indeed, on Dominica, nocturnally active invasive A. cristatellus, that arrived around 2000 and competes with its native sister species [29,30], are presumed to fill an empty niche given the low number of nocturnally active herpetofauna species [27].…”