Defensive phragmosis and cathaptosis in Trichoptera larvae

Phragmosis, or the use of specially modified body parts and associated behaviors to block an opening as defense against predators, is a commonly observed phenomenon in certain ants and termites that block entrances of their subterranean nests with large, flat heads. It has been reported in some beetles and other insects and even in some frogs. Common features of phragmosis in caddisfly larvae include a hard and usually flat body surface, with or without stout spines, and the behavior of fitting that body surface tightly in the opening of its case. A different defensive strategy occurs in snails and case-making larvae of camptosomate leaf beetles (Chrysomelidae: Cryptocephalinae and Lamprosomatinae) that protect themselves from predators by securing the openings of their shells or cases firmly against the substrate, a behavior we call “cathaptosis.” Common features of cathaptosis in caddisfly larvae include a case with its vulnerable opening oriented parallel with the substrate and accom..., To test our hypothesis for phragmosis, we observed the predator-prey interaction of case-making larvae of two Trichoptera species found locally in the Southern Appalachian Mountains when confronted with predators common in their habitats. The larva of Goera calcarata Banks, 1899 (Goeridae) makes a tubular case with lateral ballast stones for stability in fast-flowing water as it scrapes periphyton from the top surfaces of rocks in lotic-erosional habitats (Wiggins 1996). The larva of Fattigia pele (Ross, 1938) (Sericostomatidae) makes a case of fine sand and burrows in the sand of mountain springbrooks to gather fine organic particles (Wiggins 1996). 
Mature larvae of G. calcarata were collected from the tops of stones in a first-order stream at 34°45.366’N; 82°51.372’W, ca. 300 m a.s.l., and young larvae of F. pele were sifted from sand in a springbrook at 35°22.2’N; 83°6.6’W, ca. 1,520 m a.s.l. Available predators at those sites included larvae of Acroneuria abnormis (Newman, 1838) (P..., , # Defensive phragmosis and cathaptosis in Trichoptera larvae

The four videos in this dataset show behavioral responses of Trichoptera larvae to predatory threats, including evidence of phragmosis by *Fattigia pele* (Sericostomatidae) and *Goera calcarata* (Goeridae) and of cathaptosis by *Ascalaphomerus* sp. (Calamoceratidae).

## Description of the data and file structure

When disturbed by a potential predator, a larva of *Fattigia pele* or *Goera calcarata* withdraws into its protective portable case, blocking the case entrance with a hard and usually flattened head or head-and-thoracic notum, demonstrating phragmosis.

When disturbed by a potential predator, a larva of *Ascalaphomerus* sp. grasps the substrate, forcing the entrance of its protective portable case against the substrate to exclude the predator, demonstrating cathaptosis.

## Sharing/Access information

Links to other publicly accessible locations of the data include the following:

*
*
*
*

## Code/Soft...