Innate immunity of Florida cane toads: how dispersal has affected physiological responses to LPS

Stress and immunity: Field comparisons among populations of invasive cane toads in Florida

“…Over 60 years since their release in South Florida, cane toad populations have dispersed up to 450 km north (U.S. Geological Survey, 2020). As they have high invasive potential, cane toads have been used as an ectotherm model in ecoimmunology and invasion biology studies covering a wide diversity of topics including: history and geographical dispersal effects on locomotor and reproductive behavior (Brown, Holden, Shine, & Phillips, 2018; Brown, Kelehear, & Shine, 2011; Gruber, Brown, Whiting, & Shine, 2017; Kelehear & Shine, 2020; Kosmala, Christian, Brown, & Shine, 2017), corticosterone (CORT) immune interactions (Brown, Kelehear, Shilton, Phillips, & Shine, 2015; Brown, Phillips, Dubey, Shine, 2015; Brown, Shilton, & Shine, 2011; Brown, Shilton, Phillips, & Shine, 2007; S. T. Gardner, Assis, Smith, Appel, & Mendonça, 2020; S. Gardner et al, 2018; Graham, Kelehear, Brown, & Shine, 2012; Llewellyn et al, 2012), parasitic load (Phillips et al, 2010), genetic and phenotypic modifications (Rollins, Richardson, & Shine, 2015; Stuart, Shine, & Brown, 2019), and interactions of these invasive toads with native fauna (Brown & Shine, 2014; Mayer et al, 2015).…”

Differences in morphology and in composition and release of parotoid gland secretion in introduced cane toads (Rhinella marina) from established populations in Florida, USA

“…While the likelihood of secretion in laboratory-acclimated toads collected during 2019 increased with increasing doses of epinephrine, there was no difference in likelihood of secretion between northern (NPR) and southern (Miami) toad populations. The similarities in sympathetic sensitivity may have resulted from the toads being removed from the field and acclimated to the same laboratory environment prior to epinephrine injection, although altered corticosterone responses to novel stressors were still observed between toads from these populations in the study of metabolism and immune response by Gardner et al (2020). Further studies to assess whether differences in sympathetic sensitivity between northern and southern populations are related to epinephrine release could help to elucidate the responses to injected epinephrine.…”

“…In May 2019, 58 additional toads ( n = 28 Miami, and n = 30 NPR) were collected and maintained under laboratory conditions, detailed by Gardner et al. (2020). Following acclimation, the toads were divided into five treatment groups: normal saline solution (NSS) and NSS with 0.125 µm, 0.25 µm, 0.5 µm, or 1 µm epinephrine gram of body per mass.…”

“…Although these behaviors have yet to be observed for toads in Florida, toads near the northern edge populations have shown elevated baseline corticosterone concentrations and attenuated responses to a restraint challenge when compared to individuals from southern core populations (Assis et al, 2020). This pattern of attenuated response to novel stressors has also been documented under laboratory conditions for Florida cane toads (Gardner et al, 2020).…”

“…Members of the toad species Bufo bufo occupying regions of elevated anthropogenic disturbance differ in toxicity compared to those in less disturbed agricultural areas (Bókony et al., 2019), and individuals of Bufo boreas exposed to increased predation cues prior to metamorphosis had higher concentrations of more toxic compounds in their secretions (Benard & Fordyce, 2003). Altered morphological and physiological changes have been documented in R. marina at the invasion front when compared to longer established populations (Friesen & Shine, 2019; Gardner et al., 2020). Parotoid gland size has been shown to increase with body size (snout‐vent length (SVL)) in R. marina (Phillips et al., 2007; Phillips & Shine, 2005).…”