Abstract:
The invasive cane or marine toad (Rhinella marina) has spread across much of Australia since its initial introduction in 1935. Naturally found in Central and South America, R. marina was introduced to Northern Queensland to control cane insect pest populations. This study was conducted at Lake Ainsworth, Lerui.ox Head, New South Wales, Australia to determine if there was sexual dimorphism amoflg ~dult males, adult females, and juveniles by measuring snout-vent length (SVL) and weight. Additional research objectives included determining aquatic range dispersal between adult male and female cane toads, and stomach contents of adult male, adult female, and juvenile by prey order and abundance. There were significant differences detected between SVL of males with small testes (80.00 ± 9.35) and males with developed testes (102.1 ± 11.3, p = 0.007), SVL between gravid females (111.4 ± 16.1) and non-gravid females (95.7 ± 12.1,p = 0.039), and weight between male cane toads (90.9 ± 31.3) and gravid females (145.6 ± 66.7,p = 0.011). There was no significant difference in weight between males (90.9 ± 31.3) and non-gravid females (82.1 ± 34.0, p = 0.506), or SVL between males (102.1 ± 11.3) and females (103.6 ± 16.1, p = 0.637). Insect orders in the stomach contents of R. marina included Coleoptera, Hymenoptera, Arachnida, Diptera, Blattodea, Isoptera, Hemiptera, Orthoptera, Odonata, and Dermaptera! . This species likely competes with native species found in the area such as: Limnodyn4sles terraereginae, Liloria caeruiea, Liloria nasuta, Liloria chloris, Liloria brevipalmala, Limnodynastes peronii, Litoria pe ron ii, Crinia signifera, Liloria fallax, Limnodynastes ornatus, Liloria gracilenta, and Liloria tyleri, which also feed on small insects. Several other native species of anurans from New South Wales such as Pseudophryne corroboree, P. dendyi, P. bibroni, Crinia signifera, and Hyla verreauxi had stomach contents that contained the orders Collembola, Coleoptera, Hymenoptera, Formicidae, Hemiptera, Diptera, Acarina, Araneae, Orthoptera, Odonata, and Diplopoda, suggesting that cane toads compete directly for food resources with the native species.
