by Tobias J. Hauke & Volker Herzig

Study by Shivambu et al. (2020):

The first study was published by Shivambu et al. (2020) and examined the supply of tarantulas in the South African pet trade. To this end, these authors performed online searches, visited pet stores and conducted their own survey to examine which species are traded in South Africa and which are the most popular ones. Furthermore, some samples of tarantulas offered for purchase were taken for DNA barcoding in order to confirm whether their taxonomic identity matched the name under which they were traded. Finally, the authors discussed the potential of escaped/released tarantulas to become invasive species in South Africa.

In total, 3373 specimen from 195 different tarantula species were advertised for sale in South Africa in the examined time period (between 2015 and 2016). The most popular species were Tliltocatl albopilosus (199 specimen), Tliltocatl vagans (132 specimen), Grammostola rosea (120 specimen), Nhandu tripepii (103 specimen) and Grammostola pulchripes (101 specimen).

Herein, we extracted the data from Shivambu et al. (2020; provided in the Supplementary material of their study) and added all species counts per corresponding genus in order to provide a genus level ranking of the top 30 most popular tarantulas (see Table 1). Based on this ranking, the top 5 most popular tarantula genera are Tliltocatl, Brachypelma, Poecilotheria, Grammostola and Nhandu.

Study by Hauke & Herzig (2021):

The second study was published by ourselves (Hauke & Herzig, 2021). We gathered 354 spider bite and scorpion sting incidents from specimens that were kept as pets in order to gain new insights on the circumstances and outcomes of arachnid envenomations and also to perform a risk assessment for the keeping of venomous arachnids as pets. We also wanted to correlate the number of bite/sting incidents for the respective genera with their prevalence in the hobby in order to find out, whether certain genera are overrepresented (e.g. because these arachnids are particularly willing to bite/sting) or underrepresented (e.g. because these arachnids are particularly reluctant to bite/sting) among the biting/stinging arachnids. To this end, we required a popularity ranking with actual numbers. In order to get an educated estimate for a popularity ranking, we relied on the large number of pet keeping handbooks covering arachnids or “exotic pets”, which usually contain specific sections that introduce the most common species. From these handbooks, we then extracted how often each genus is mentioned in order to establish a “popularity ranking” for spider (and also scorpion) genera in the hobby. Most of the authors of these handbooks were from Europe (e.g. Germany, France, UK) with one being from the USA – so a rather international selection. Accordingly, 69 different tarantula genera were mentioned in these handbooks and the top 5 most popular genera were Brachypelma, Poecilotheria, Avicularia, Grammostola and Haplopelma (see Table 1 for the top 30).

Discussion:

There are currently 1030 described species grouped in 154 genera within the spider family Theraphosidae (WSC, 2022) and a large proportion (i.e. several hundred) of these are present in the tarantula keeping hobby. Rankings on which of these genera are the most popular ones amongst tarantula keepers were only elucidated recently by two separate studies. One study (Hauke & Herzig, 2021) counted genus representations within the specific sections of popular handbooks for tarantula or “exotic pet” keepers, while another study (Shivambu et al., 2020) monitored tarantulas supplied through the pet trade. Besides employing entirely different methods, the two studies also differed in the geographic origin of their data. While our study (Hauke & Herzig, 2021) mostly used books from Europe and North America, the second study (Shivambu et al., 2020) focused on the South African pet trade. Despite these differences in methodology and data origin, there is a good correlation of the resulting popularity ranking. Table 1 shows that 70% of the top 30 genera in each study also appeared in the respective top 30 of the other study. For a closer look, we employed a linear correlation for the data from both studies (see Fig. 1). The data mostly correlate well, with few exceptions. The genera that differ most significantly between the two rankings are Tliltocatl, Nhandu, Lasiodora, Avicularia and Aphonopelma. The most apparent difference (highlighted in red in Fig. 1) is that Tliltocatl, Nhandu, and Lasiodora have a higher popularity ranking in the Shivambu et al. (2020) study, whereas Avicularia and Aphonopelma are more popular in our study (Hauke & Herzig, 2021). For most other genera, there is otherwise a good correlation of both rankings. For example, both Brachypelma and Poecilotheria are in the top 3 of both studies, indicating that these two genera indeed are amongst the most popular tarantula genera represented in the hobby.

Brachypelma and Poecilotheria are also the only Theraphosid genera, which are completely listed under the “Convention on International Trade in Endangered Species of Wild Fauna and Flora” (in short: CITES). In addition, only the species Aphonopelma pallidum, Sandinista lanceolatum, Sericopelma angustum, Sericopelma embrithes as well as all Tliltocatl species should have the CITES conservation status as they were previously in the genus Brachypelma and only switched to other genera due to more recent taxonomic changes (Cooper et al., 2019; Mendoza & Francke, 2020). All CITES listed tarantulas are under Appendix II and as stated by CITES (2022), this appendix “includes species not necessarily threatened with extinction, but in which trade must be controlled in order to avoid utilization incompatible with their survival.” That means that those spiders protected by international trading regulations are also among the most popular tarantula pets in the hobby. Fortunately, both Brachypelma and Poecilotheria species are regularly bred by enthusiasts and successful breeding can even result in 200 (for Poecilotheria) to 600 (for Brachypelma) offspring (Krehenwinkel et al., 2008; Striffler, 2004; Schultz & Schultz, 1998; Cléton et al., 2015). Accordingly, we assume that the global demand in these popular tarantulas can mostly be met by captive breeding, making this hobby quite sustainable. And this assumption is well supported by the “CITES Trade Database”: Basically, all Brachypelma, which were internationally (and officially) traded in the last decade, were captive bred (CITES, 2022).

We conclude that any potential correlation between the popularity of certain tarantula genera in the pet keeping hobby and the level of endangerment in their natural habitat is mostly coincidental and not causative, particularly given that many tarantulas in the pet keeping hobby are regularly bred in captivity. Most notably, there are other major threats such as the highly unsustainable collection of tarantulas for food products in Cambodia (Yen & Ro, 2013), the collection as tourist souvenirs in Malaysia (Smith, 2011) and the ongoing habitat destruction globally (Branco & Cardoso, 2020). In our opinion, these threats have a more significant impact on wild tarantula populations than the collection for the international pet trade. Conversely, if conservationists and scientists teamed up with enthusiastic tarantula breeders, this could even facilitate the gain of biological knowledge and help to conserve potentially endangered tarantula species at least in human care.