The UPLB Museum of Natural History’s Biodiversity Seminar last 28 June 2016 at the MNH Conference Room recently featured Associate Professor of Biology at Texas A&M International University (TAMIU) Dr. C. Neal McReynolds who presented his research on striped bark scorpions.

More than a dozen faculty and students attended the seminar where Dr. McReynolds discussed at length the foraging behavior of striped bark scorpions (Centruroides vittatus) found in the blackbrush environs of Laredo, Texas, a result of more than a decade of research he has done with his mentor and students.

C. vittatus is a very common scorpion in Laredo, Texas as well as in the United States which causes thousands of cases of non-lethal stings on humans each year. But although the scorpion is normally encountered by people in Laredo, its eating behavior has not much been much researched on.

“The striped bark scorpion is nocturnal and it hides during the day,” according to Dr. McReynolds. To locate and observe these arachnids in the dark, ultraviolet (UV) lights are needed. “One of the unique traits of scorpions is they fluoresce when exposed to UV light, giving off a cyan-like tint in the dark,” McReynolds said.

During his presentation Dr. McReynolds talked on different aspects of the striped bark scorpion’s foraging behavior in a habitat composed mostly of blackbrush (Vachella rigidula), legumes and succulents such as cacti. “In our research, we tried to determine what prey do scorpions capture, what factors affect prey capture, and where do scorpions forage and how does that affect prey capture,” McReynolds explained.

With the studies he has lead, he has been able to categorize the observed scorpions into four size classes by measuring the scorpions’ length from the anterior prosoma, which houses the fused head and thorax, up to the posterior of the mesosoma, which bears the legs of the scorpion. Also from observations, McReynolds’ team has identified the various prey of the scorpions.

“Striped bark scorpions prey on caterpillars, orthopterans (an order of grasshoppers and crickets), moths, beetles, roaches, mantids, and spiders,” he said. “Some of the scorpions even eat their own kind, regardless of size,” he added.

“But the most important food of the scorpions, as shown by our data, are caterpillars,” McReynolds reported. “We observed that scorpions forage mostly on caterpillars regardless of its size class and the foraging season,” he explained.

“But the one observation that really stands out is that size class III scorpions (10-15 mm) are able to prey on more caterpillars than any other size classes,” said Dr. McReynolds as he presented different comparisons made on the variables his research has gathered.

Dr. McReynolds’ research has also been able to identify ways how the scorpions catch their different prey. “C. vittatus catch moths through a sit-and-wait method and actively search and hunt for caterpillars in the vegetation.

Dr. McReynolds proceeded thereafter to throwing research questions that can further be looked into such as how scorpions handle their prey as well as how differences in the locations where these scorpions forage affect their behavior.

Before the event came to a close, Dr. McReynolds acknowledged the support of several parties involved in the research including two of his students who were present during the seminar.

Dr. McReynolds is currently co-leading a TAMIU study abroad program in the Philippines which has partnered with the Museum of Natural History to expose international students to tropical ecology.


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