Responses to Femoral Gland Secretions by Visually Adept Male and Female Collared Lizards

Abstract

Although visually transmitted social signals are well documented in many diurnal iguanians, including collared lizards, secretory femoral glands also suggest a role of chemical signals in intraspecific communication. We conducted laboratory trials to test the extent to which male and female collared lizards responded by tongue‐flicking femoral gland secretions, neutral (water), and odoriferous (cologne) control substances, males distinguished self‐secretions from those produced by unfamiliar rival males, and females distinguish secretions from unfamiliar vs. familiar males. Both males and females spent similar amounts of time in four arena quadrants each with a Petri dish treated with one of the four test compounds. Males gave more tongue flicks/trial to secretions produced by unfamiliar rivals and cologne than they tongue‐flicked their own secretions and water. By contrast, the number of tongue flicks by females on control substances and familiar and unfamiliar males was similar. Results support the hypothesis that femoral gland secretions function in intrasexual signaling among male collared lizards, perhaps allowing them to distinguish unfamiliar rivals. Females tongue‐flicked secretions from familiar and unfamiliar males with similar frequency that was high relative to that of males, suggesting a possible role of secretions in assessment of males. Ours is the first evidence of a signaling role of femoral gland secretions in collared lizards and adds to a growing body of evidence that chemical signaling has evolved in diurnal lizards that also have highly developed visual‐based signaling.

Morph-specific protein patterns in the femoral gland secretions of a colour polymorphic lizard

“…), and are among the most suitable signals in territorial contests 131 . Indeed, typically territorial species are able to recognize familiars on a chemical basis 50,74–76,132 , and also to build a spatial map of scent marking points 133 . In a CP system, assessing the morph identity of a potential rival or mate without (or before) seeing it (i.e., before the visual modality can be activated) may give a great advantage in decision-making and allows better tuning intraspecific interaction 12,39 .…”

“…Notably, on the receiver side, chemoreception is powered by the vomeronasal organ associated to a forked tongue and the tongue-flicking behaviour 58–61 . On the signaller side, most lizards species have a series of specialized epidermal glands in the femoral and/or pre-cloacal region 62–64 producing waxy secretions used to convey information about many signaller’s traits, like species 65–67 , sex 68–70 , identity 71–73 , familiarity 50,74–76 , status 77–80 , and condition 81,82 . Therefore, the chemical path comes as the ideal channel being combined to the visual modality explicitly recalled by CP.…”

In Space and Time: Territorial Animals are Attracted to Conspecific Chemical Cues

“…The same receiver may display a modified response due to altered gene expression following experience (Immonen & Ritchie 2012), or due to changes in the animal host’s gastrointestinal microbial community shown to influence brain processes linked to mate preferences (Ezenwa et al 2012; Foster & McVey Neufeld 2013). Furthermore, sex differences in physiology can predict both time spent producing chemosensory behavior (Clapham et al 2014) and odor preferences (Dantzer & Jaeger 2007; Whittaker et al 2011, 2013; Baird et al 2015). In this study, we compare the space use responses of territory holders to temporary visitors, and females to males, in response to conspecific odor cues.…”

Inter- and intra-population variability of the protein content of femoral gland secretions from a lacertid lizard

“…This result agrees with those obtained on desert iguanas ( Alberts 1991 , 1992 ) and green iguanas ( Alberts et al 1993 ), and supports the hypothesis that each lizard has its own protein profile, which may therefore be used to signal identity ( Alberts 1990 ). Indeed, the ability of some lizard species (also lacertids) to recognize their conspecifics by means of chemical cues alone has been already proved ( Alberts 1992 , 1993 ; Aragón et al 2001 ; Mason and Parker 2010 ; Font et al 2012 ; Baird et al 2015 ), suggesting that differences in chemical compounds at the individual level could actually occur and can be reliably used for individual recognition. Further, the stability of the protein composition within individuals found in iguanas ( Alberts 1990 ) and the stronger relationship between proteins and genes makes them the ideal candidate to serve as an identity marker, as already found in mammals ( Mus musculus ; Hurst et al 2001 ) and fishes ( Gasterosteus aculeatus , Milinski et al 2005 ).…”