Monitoring and modeling non-native invasive green iguana population response to harvesting on Grand Cayman, Cayman Islands.

Registered hunters harvested over 1.3 million non-native invasive green iguanas (Iguana iguana) on Grand Cayman between October 2018 and August 2021. We used islandwide post-reproduction survey-based abundance estimates in August 2014-2021 and model-based abundance predictions for August 2022-2030 to assist natural resource managers with reassessment and modification of the harvest strategy due to diminishing returns to hunters paid per green iguana harvested. We need harvest rates > 0.600 for desired abundance ≤ 50,000 and > 0.700 for desired abundance ≤ 10,000 green iguanas. With harvest rates < 0.600, the population would likely remain above desired abundance. Without harvesting, the green iguana population would likely reach carrying capacity by August 2026.

Systemic Helicobacter infection and associated mortalities in endangered Grand Cayman blue iguanas (Cyclura lewisi) and introduced green iguanas (Iguana iguana).

The Blue Iguana Recovery Programme maintains a captive breeding and head-starting program for endangered Grand Cayman blue iguanas (Cyclura lewisi) on Grand Cayman, Cayman Islands. In May 2015, program staff encountered two lethargic wild Grand Cayman blue iguanas within the Queen Elizabeth II Botanic Park (QEIIBP). Spiral-shaped bacteria were identified on peripheral blood smears from both animals, which molecular diagnostics identified as a novel Helicobacter species (provisionary name Helicobacter sp. GCBI1). Between March 2015 and February 2017, 11 Grand Cayman blue iguanas were identified with the infection. Two of these were found dead and nine were treated; five of the nine treated animals survived the initial infection. Phylogenetic analysis of the 16S rRNA gene suggests Helicobacter sp. GCBI1 is most closely related to Helicobacter spp. in chelonians. We developed a Taqman qPCR assay specific for Helicobacter sp. GCBI1 to screen tissue and/or blood samples from clinical cases, fecal and cloacal samples from clinically healthy Grand Cayman blue iguanas, including previously infected and recovered iguanas, and iguanas housed adjacent to clinical cases. Fecal and/or cloacal swab samples were all negative, suggesting that Grand Cayman blue iguanas do not asymptomatically carry this organism nor shed this pathogen per cloaca post infection. Retrospective analysis of a 2014 mortality event affecting green iguanas (Iguana iguana) from a separate Grand Cayman location identified Helicobacter sp. GCBI1 in two of three cases. The source of infection and mode of transmission are yet to be confirmed. Analysis of rainfall data reveal that all infections occurred during a multi-year dry period, and most occurred shortly after the first rains at the end of seasonal drought. Additionally, further screening has identified Helicobacter sp. GCBI1 from choanal swabs of clinically normal green iguanas in the QEIIBP, suggesting they could be asymptomatic carriers and a potential source of the pathogen.

Lateralisation of trunk movements in captive Asian elephants (Elephas maximus).

Behavioural lateralisation has been widely investigated in vertebrates. Most studies in this area have focused on laterality in paired organs such as hands, limbs, and eyes. Fewer studies have explored side preferences in unpaired organs such as tails or trunks. We investigated laterality of trunk use among captive Asian elephants (Elephas maximus), quantifying side preference in four different trunk movements: feeding, sand spraying, self-touching, and swinging. We found evidence for significant side preference in all four movement categories. Variation in the occurrence and direction of side preference was seen both within and between individuals but no overall population-level side bias was seen for any of the four trunk movements. The strength of side preference in trunk use was significantly higher for feeding than for self-touching and swinging. This study adds to the very limited data on laterality in unpaired organs generally, and elephants' trunks more specifically. In addition it provides novel information about directional lateralisation in trunk use across a range of functionally distinct contexts.