20 December, 2019

The effects of human activities on the scorpion fauna

Human activities and habitat change or destruction will have an impact on the scorpion fauna in an area in different ways. Some species die out, some move, while others are able to adapt to the new circumstances. Knowledge about this is important to be able to preserve biodiversity in vulnerable areas.

Andre Lira and co-workers published this fall a study from Brazil on the effects of human activities and habitat changes in Neotropical forests. Not surprisingly effects where observed, but they were different among the involved species. The contrasting responses of scorpion species in this study to anthropogenic land-use may offer an insight into a differential ecological plasticity of this taxa.

Changes in land-cover driven by human activities is one of the main causes of disturbances on natural communities but the impact of this factor on scorpions assemblages remains scarcely know. Here we analyzed the scorpion fauna in five tropical forests and their respective neighboring non-natural matrix (planted forests or crops) in Brazil (n = 4) and Mexico (n = 1), aiming to understand how different species of scorpions respond to land-use changes. Scorpions were actively collected with the help of a UV flashlight. A total of 461 individuals were sampled, belonging to nine species and seven genera distributed in three families Buthidae, Bothriuridae and Diplocentridae. Differences in assemblages between environments were found, with higher gamma diversity in undisturbed environments where species showed the highest abundance. A higher species turnover was found in disturbed environments. Based on these results, we suggest a differential sensitive reaction to habitat  lterations amongst scorpions species.

Lira AFA, Pordeus LM, Salomão RP, Badillo-Montaño R, Albuquerque CMR. Effects of anthropogenic land-use on scorpions (Arachnida: Scorpiones) in Neotropical forests. International Journal of Tropical Insect Science. 2019:1-8. [Subscription required for full text]

Thanks to Andre Lira for sending me their article!

Female scent turns scorpion males on

The ability of males to find females and behave correctly is important in most animals, and especially in species where the individuals are solitary and aggressive,with females sometimes cannibalizing males. It is well known that male scorpions are able to detect previous presence of females by reacting to chemical substances left by the females (many of us have seen males "juddering" when standing on a substance where a female has previously visited).

Laís Pordeus and co-workers have recently published a study on Tityus pusillus Lourenço, 2013 (Buthidae) where they present evidence that males are changing their behavior in the presence of female scent and that the odor of the females also triggers courtship behavior in the males.

Recognizing conspecific individuals from other members of the community is important for many interactive behaviors, especially those involved in mate selection. We investigated whether male courtship behavior is triggered by chemical cues left by females on the substrate using the sedentary litter-dwelling scorpion Tityus pusillus Pocock, 1893, which is a small and common species distributed throughout the northeast Atlantic Forest in Brazil. In experiments using 50 pairs, we tested whether males recognize females by detecting sex-specific chemicals on the substrate. All males changed their behavior, performing pre-courtship acts when exposed to female-specific chemicals on the substrate, but they did not change their behavior when exposed to a clean substrate lacking female-specific chemicals. These results show that the male T. pusillus alters its behavior in the presence of female chemical cues, suggesting that males recognize females by detecting compounds left on the substrate and that the presence of these chemicals trigger the courtship behavior of the male T. pusillus.

Reference:Pordeus LM, Lira AFA, Albuquerque CMR. Male courtship behavior is triggered by female chemical cues in the scorpion Tityus pusillus (Scorpiones: Buthidae). Can J Zool. 2019;97:1122-5. [Subscription required for full text]

Thanks to Laís Pordeus for sending me their article!

19 December, 2019

Scorpions can actually smell their enemies

It has been known for a long time that scorpions can smell (detect chemical substances) with their pectines and pedipalpal fingers. Zia Nisani and Raul Curiel report for the first time that scorpions are also able to smell the presence of potential predators. In a research trial they were able to show that individuals of Hadrurus arizonensis (Ewing, 1928) (Caraboctonidae) changed behavior in the presence of odor from a potential predator. The advantages of such an ability is of course quite obvious.

Sensory ecology studies show that reception and utilization of information from the environment is a crucial life process. Scorpions possess a weapon that can be used against predators, but it remains unknown whether scorpions’ decision to use it is influenced by chemical cues from predators. We investigated the influence of predators’ odors on stinging behavior of Hadrurus arizonensis (Ewing, 1928) by stimulating them to sting under two conditions: in the presence of an odor from a potential rodent predator (Rattus norvegicus) and in the absence of such an odor. It took fewer probes to elicit a response when predator scent was present, and it resulted in more wet stings than the non-scented treatments. Finally, the smaller scorpions were more reactive than the larger ones. The variances in stinging behavior suggest that the detection of predator odors by H. arizonensis elevates its response in potentially threatening circumstances.

Nisani Z, Curiel R. Antipredator responses of Hadrurus arizonensis (Scorpiones: Caraboctonidae) to chemosensory cue from a mammalian predator. J Arachnol. 2019;47:389-91. [Open Access]

17 December, 2019

Five new species of Reddyanus from Southeast Asia

Frantisek Kovarik and Frantisek Stahlavsky have recently published a revision of the rare genus Reddyanus Vachon, 1972 (Buthidae) from Southeast Asia. Five new species are described.

Reddyanus furai Kovarik & Stahlavsky, 2019 (Vietnam)

Reddyanus hofereki Kovarik & Stahlavsky, 2019 (Malaysia)

Reddyanus Majkusi Kovarik & Stahlavsky, 2019 (Malaysia)

Reddyanus rolciki Kovarik & Stahlavsky, 2019 (Vietnam and Cambodia)

Reddyanus schwotti Kovarik & Stahlavsky, 2019 (Thailand and Cambodia)

An identification key for the genus in Southeast Asia is included.

Five new species are described: Reddyanus furai sp. n. from Vietnam, R. hofereki sp. n. and R. majkusi sp. n. from Malaysia, R. rolciki sp. n. from Vietnam and Cambodia, and R. schwotti sp. n. from Thailand and Cambodia, fully complemented with color photographs of live and preserved specimens, as well as their habitats. New species are compared with all other species from this region. In addition to the analysis of external morphology, we also describe the karyotypes of R. furai sp. n. (2n=14), R. majkusi sp. n. (2n=16), R. rolciki sp. n. (2n=14), and R. schwotti (2n=11). A key and distribution map to Reddyanus Vachon, 1972 in Southeast Asia (14 species) are included.

Kovarik F, Stahlavsky F. Revision of the genus Reddyanus from Southeast Asia, with description of five new species from Cambodia, Malaysia, Thailand and Vietnam (Scorpiones: Buthidae). Euscorpius. 2019(295):1-45. [Open Access]

Family Buthidae

05 December, 2019

Two new species of Neobuthus from Somaliland

Frantisek Kovarik has recently described two new species of Neobuthus Hirst, 1911 (Buthidae) from Somaliland.

Neobuthus haeckeli Kovarik, 2019

Neobuthus solegladi Kovarik, 2019

New information about taxonomy and distribution of the genus Neobuthus Hirst, 1911 is presented, based on material recently collected in Somaliland. N. awashensis Kovařík & Lowe, 2012 is reported from Somaliland for the first time. Two new species are described, N. haeckeli sp. n. and N. solegladi sp. n. An updated distribution map of the genus Neobuthus is provided.

Kovarik F. Scorpions of the Horn of Africa (Arachnida, Scorpiones). Part XXII. Two new species of Neobuthus from Somaliland (Buthidae). Euscorpius. 2019(294):1-16. [Open Access]

Family Buthidae