29 June, 2022

How does Paruroctonus utahensis find its way home


Finding the way home is an important skill for burrowing scorpions like Paruroctonus utahensis (Williams, 1968) (Vaejovidae). There have been some indications that scorpions use a view-based navigational process termed "Navigation by Scene Familiarity", which has been seen in bees and ants. Douglas Gaffin and co-workers have recently published a study where they investigate if scorpions may be guided by tastes and touches acquired via their mid-ventral pectines, instead of or in addition to vision.

The authors have named this form of homing "The Navigation by Chemotextural Familiarity Hypothesis (NCFH)". In their study they find evidence of learning walks during burrowing in Paruroctonus utahensis and they conclude that these putative learning walks, together with recently reported path integration in scorpions, may provide the crucial home-directed information requisite for NCFH. 

The navigation by chemo-textural familiarity hypothesis (NCFH) suggests that scorpions use their midventral pectines to gather
chemical and textural information near their burrows and use this information as they subsequently return home. For NCFH to be viable, animals must somehow acquire home-directed ‘tastes’ of the substrate, such as through path integration (PI) and/or learning walks. We conducted laboratory behavioral trials using desert grassland scorpions (Paruroctonus utahensis). Animals reliably formed burrows in small mounds of sand we provided in the middle of circular, sandlined behavioral arenas. We processed overnight infrared video recordings with a MATLAB script that tracked animal movements at 1–2 s intervals. In all, we analyzed the movements of 23 animals, representing nearly 1500 h of video recording. We found that once animals established their home burrows, they immediately made one to several short, looping excursions away from and back to their burrows before walking greater distances. We also observed similar excursions when animals made burrows in level sand in the middle of the arena (i.e. no mound provided). These putative learning walks, together with recently reported PI in scorpions, may provide the crucial home-directed information requisite for NCFH.

Gaffin DD, Munoz MG, Hoefnagels MH. Evidence of learning walks related to scorpion home burrow navigation. J Exp Biol. 2022;225:jeb243947. [Open Access]

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