Size (or age) influence activity and habitat use in Centruroides vittatus

Earlier this Fall, Neal McReynolds published a study on ontogenetic shifts in microhabitat use, foraging and temporal activity for Centruroides vittatus (Say, 1821) (Buthidae). I haven't had the time to read the paper until now, so sorry for late blogging.The abstract sums the study up pretty well.

Abstract:
Ontogenetic shifts in activity and habitat use by the scorpion Centruroides vittatus in Laredo, Texas can occur with shifts in microhabitat use, the height of the scorpion in vegetation and seasonal and lunar activity among different sizes of C. vittatus but not taxa of prey in the diet. The microhabitat use by the different size classes was significantly different with significant associations among the cacti with a high frequency of larger scorpions on prickly pear cactus and strawberry cactus and between grass and other vegetation with a high frequency of smaller scorpions on grass. A comparison of the mean height of scorpion on blackbrush among the size classes was not significant but height on grass was significant. The activity of the size classes was significantly different among months and lunar cycle. Temperature had a significant effect on the activity of scorpions by different size classes and in different microhabitats. Caterpillar availability did not have a significant association with either scorpion size class or microhabitat use by scorpions. The taxa of prey captured by the different size classes were not significantly different including no notable difference in scorpions feeding on caterpillars. The size classes of C. vittatus show microhabitat and temporal shifts in activity. The results suggest that smaller scorpions can possibly be avoiding the larger scorpions by reducing activity in the preferred microhabitat (prickly pear and strawberry cactus) of larger scorpions.

Reference:
McReynolds CN. Ontogenetic Shifts in Microhabitat Use, Foraging and Temporal Activity for the Striped Bark Scorpion Centruroides vittatus (Scorpiones: Buthidae). Euscorpius. 2012 (144):1-19. [Free full text]

Ecology of Microtityus jaumei in Cuba

Franklyn Cala-Riquelme and Marco Colombo have published a study on the ecology of the small scorpion Microtityus jaumei Armas, 1974 (Buthidae) in Sierra de Canasta in Cuba.

Abstract:
An assessment of the population dynamics of Microtityus jaumei Armas (Scorpiones: Buthidae) on the slopes south of Sierra de Canasta, Guantánamo Province, Cuba show an increase in activity over the year (≤ 0.05). The activity peak is related to the reproductive period from June to November. The abundance of scorpions was significantly related to density of the canopy and thickness of the substrate.

Reference:
Cala-Riquelme F, Colombo M. Ecology of the scorpion, Microtityus jaumei in Sierra de Canasta, Cuba. Journal of Insect Science (Tucson). 2011;11(Article 86):1-10. [Free full text]

Density, spatial distribution and biomass of Hoffmannihadrurus gertschi

Ana Quijano-Ravell and co-workers have recently published an article on the density, spatial distribution and biomass of Hoffmannihadrurus gertschi (Soleglad, 1976) (Caraboctonidae)* in an area in Mexico.

The paper is written in Spanish so I have only read the English abstract.

[*The authors have placed this species in Hadrurus, but it was transfered to Hoffmannihadrurus by Fet & Soleglad i 2008 and this species is listed as Hoffmannihadrurus gertschi (Soleglad, 1976) in The Scorpion Files. Some scientists disagree on the validity of Hoffmannihadurus, as this paper is an example of. Also, some scientists choose to put Hadrurus in Iuridae and reject the validity of Caraboctonidae. See details here.]

Abstract:
Density, spatial dispersion and biomass of Hadrurus gertschi Soleglad 1976 were estimated from field data obtained during a year of observations at “La Coronilla” hill in the municipality of Tepecoacuilco de Trujano, Guerrero, Mexico. Five quadrants of 400 m2 with differing slope exposures were used. The highest density was recorded in the quadrant without slope or “flat quadrant” with 0.3450 burrows per m2 and the southern exposure quadrant (0.2300 burrows per m2). The lowest densities occurred in the quadrants with northern and western exposures (0.1325 and 0.0825 burrows per m2 respectively). The highest values of the year were recorded in the months of May to July. The spatial dispersion of burrows in all exposures studied corresponds with a clumped distribution according to the Morisita Index. Average dry weight of adults was 2.22 ± 0.73 g and 6.4 ± 0.89 g in fresh weight. The juveniles weighted 0.08 ± 0.05 g in dry weight and 0.2 of fresh weight instar II and 1.10 ± 0.41 g dry weight and 3.63 ±1.95 g in fresh weight in the preadult stage. The biomass per ha was estimated in 2471.26 g of dry weight and 6190.02 g of fresh weight.

Reference:
Quijano-Ravell AF, Ponce-Saavedra J, Francke OF. Densidad, distribucion espacial y biomasa de Hadrurus gertschi Soleglad (Scorpiones, Iuridae) en una localidad de Guerro, Mexico. Revista Iberica de Arachnologia. 2012;20:35-43.

Thanks to Dr. Francke for sending me this paper!

Family Caraboctonidae

A new species of Urophonius from Argentina

Andreas Alejandro Ojanguren-Affilastro and German Cheli have published a study with data on the genus Urophonius (Bothriuridae) from Patagonia, Argentina. A new species is described:

Urophonius martinezi Ojanguren-Affilastro & Cheli, 2009

Distribution and seasonal surface activity of the genus Urophonius are also disscussed. Interestingly, most species of the genus Urophonius seem to have tehir surface acitvity period in the winter.

Abstract:
New data on the distribution and systematics of Patagonian species of the scorpion genus Urophonius Pocock 1893 are provided. A species of this genus from Penı´nsula Valde´s in central eastern Argentinean Patagonia, Urophonius martinezi new species, is described. The surface activity period of most of the species of the genus is reviewed and clearly established. A distribution map as well as a key for the Patagonian species of the genus are provided.

Reference:
Ojanguren-Affilastro AA, Cheli G. New data on the genus Urophonius in Patagonia with a description of a new species of the exochus group (Scorpiones: Bothriuridae). Journal of Arachnology. 2009;37(3):346-56. [Subscription required for fulltext, but free fulltext after 12 months]

Family Bothriuridae