An assessment of alien terrestrial invertebrate species in the pet trade in South Africa

Abstract

Many species have been introduced throughout the globe for the pet trade and some have escaped or been released from captivity and become invasive. In South Africa, different terrestrial invertebrate species are offered for sale in pet stores, on websites and by breeders. It is not known which alien terrestrial invertebrate species are traded, if the names used are correctly applied or whether these species could pose the risk of becoming invasive should they be released or escape. To determine which species are in the South African pet trade, species names were collected from pet stores, websites and via private breeders. Twenty-seven specimens from 11 species were purchased from different pet stores for DNA barcoding to determine if the species were correctly labelled. To determine if any parts of South Africa would be climatically suitable, climate match (13 species) and species distribution models (23 species) were developed for 36 terrestrial invertebrate species. The Socio-Economic Impact Classification of Alien Taxa (SEICAT) and Environmental Impact Classification for Alien Taxa (EICAT) were used to assess the recorded impacts of terrestrial invertebrate species. A total of 53 (36 recognized and 17 unrecognized) terrestrial invertebrate species were recorded as being for sale in South Africa. The most popular species were mealworms (Tenebrio molitor) (89 availability index score), superworms (Zophobas morio) (78 availability index score) and dubia roach (Blaptica dubia) (49 availability index score). Terrestrial invertebrate species are used for various purposes such as pets, food for pets, cleaners of cages and soil improvement. Out of the 11 species that were sequenced, nine species were correctly identified. The phylogenetic tree indicated that nine species clustered with reference sequences of the same species with high nodal support values while two species clustered with the same genus but not the same species names. Nine species assessed following the climate match method had suitable climate in South Africa. The model performance indicated that models were successful in predicting areas that are climatically suitable for 15 species. Impact records were available for only 18 species. The recorded socio-economic impacts were generally higher than the recorded environmental impacts. We did not find any species that had large areas that were climatically suitable and high availability and that also had high environmental or socioeconomic impacts. Overall, the risk of invasion from terrestrial invertebrate species in the pet trade appears to be low based on the species considered in this study. However, the trade is dynamic which could mean that species availability could change in future or new species could be introduced. Therefore, long term sampling is necessary to obtain a more complete list as the market appears to be dynamic.