A number of studies have empirically examined the effect of case material on the survival probability of the associated larvae (Otto and Svensson 1980; Johansson 1991; Johansson and Johansson 1992; Johansson and Nilsson 1992; Nislow and Molles 1993). The eggs hatch in a few weeks. This is a short clip taken from my full video on creatures of the pond, just to emphasize the awesomeness of what I think I saw.... caddisfly larvae who haven't yet constructed their cases! For example, Otto and Svensson (1980) found that cases made of mineral material withstood substantially greater crushing forces than cases made of leaf and bark material. Strong evidence was found that caddisfly cases operate as a defensive mechanism against potential predators. After two or three weeks the pupa bites its way out of the cocoon and swims or crawls to the water surface, using its hair-fringed middle pair of legs. Otto C, Johansson A. To determine if the diameter of the caddisfly cases differed between case types, the diameter (at the widest point) of 10 cases from each species was measured with digital calipers. These aquatic larvae manufacture cases using different materials from the environment (Mackay and Wiggins 1979). Data were transformed to meet statistical assumptions where necessary. In our study, dragonflies released the cased caddisflies almost immediately after capture, and all three case types were sufficient to protect caddisflies and increase their probability of surviving the predation event. 2006). Caddisflies build cases that function as protective armor against predators out of a variety of materials in their environment. Caddisflies are called sedges by anglers. Some species are scrapers, feeding on the film of algae and other periphyton that grows on underwater objects in sunlight. The portable cases constructed by caddisfly larvae have been assumed to act as a mechanical defense against predatory attacks.  The larvae of many species use silk to make protective cases, which are often strengthened with gravel, sand, twigs, bitten-off pieces of plants, or other debris. Twenty-four hours prior to testing, the stick-case and leaf-case caddisflies were transferred to 11-L plastic tubs, which were filled with 4 L of filtered tap water, detritus, and an aerator. (B) “Stick” case built by Limnephilus flavastellus. The posterior segment bears a pair of hooks for grappling. , Caddisflies are found worldwide, with the greater diversity being in warmer regions. They are associated with bodies of freshwater, the larvae being found in lakes, ponds, rivers, streams and other water bodies. (1987) presented empirical evidence indicating that this is indeed a function of cases in some species. About thirty families of caddisfly, members of the suborder Integripalpia, adopt this stratagem. The resulting works are sold across the world. They can often fly immediately after breaking from their pupal cuticle. On the other hand, dragonflies make direct contact with the labium when attacking the caddisfly (Corbet 1999). They share this characteristic with several distantly-related groups, namely the dragonflies, mayflies, stoneflies, alderflies and lacewings. They can tolerate low oxygen concentrations. In addition, caddisflies with this case-type may experience additional benefits that went unmeasured in our study. Some types do not make larval cases but will make net like retreats. The tube can be lengthened when the growing larva needs to feed in new areas. Other studies have documented the protection that caddisfly cases offer from predators (Otto and Svensson 1980; Johansson 1991; Johansson and Johansson 1992). Most can be divided into the suborders Integripalpia and Annulipalpia on the basis of the adult mouthparts. However, these studies did not control for the presence or absence of a case, and therefore did not determine the relative protective value of different case materials. Caddisfliy larvae often make silken nets that they deploy in the water to catch food items. Williams DD, Tavares AF, Bryant E. Respiratory device or camouflage? Glossosomatidae. Elementary studies in insect life Elementary studies in insect life elementarystudie00hunt Year: 1902 PEOTECTIVK DEVICES FIG. , About 14,500 species of caddisfly in 45 families have been recognised worldwide, but many more species remain to be described. These bowls were maintained in the 18° C environmental chamber. Yet, observations revealed that there was no difference in survival between the case types. , Caddisfly larvae are aquatic, with six pairs of tracheal gills on the underside of the abdomen. Excluding trials that did not yield an attack does not qualitatively change the results; including these data is likely a better representation of survival because these prey may possess a phenotype that is unacceptable or unpalatable to the predator. High quality figures are available online. The materials used include grains of sand, larger fragments of rock, bark, sticks, leaves, seeds and mollusc shells. The larvae exhibit various feeding strategies, with different species being predators, leaf shredders, algal grazers, or collectors of particles from the water column and benthos. Their larvae use silk to make cases of pebbles and other aquatic particles. He removes the larvae from their original cases and adds precious and semi-precious items such as grains of gold into the tank. While caddisflies in the wild construct their cases out of twigs, sand, aquatic plants, and rocks, a French artist, Hubert Duprat, makes art by providing wild caddisflies with precious stones and other materials. We are experimenting with display styles that make it easier to read articles in PMC. , Fossil caddisflies have been found in rocks dating back to the Triassic. Mackay RJ, Wiggins GB. Although most species lay eggs, a few in the genus Triplectides are ovoviviparous. A white blind was placed around the dish to minimize external visual influences and the A. junius was allowed to acclimate for 2 minutes. For example, Wissinger et al. These tubs were placed in an environmental chamber at 18° C. The detritus was prepared by placing Three case types built by caddisfly larvae used in predation experiments. Many aquatic predators forage using visual cues, and it has also been suggested that the cases function to camouflage the larva inside (Nielsen 1942). In some groups head capsules, functional mandibles, thoracic shields, abdominal gills, abdominal prolegs or hooks, and types of nets or cases are distinct. In the present study, caddisflies with one of three different case types, as well as a no-case control, were exposed to predatory dragonflies to determine whether (1) cases made of different material differentially affect caddisfly survival, and (2) what role the general presence of a case has on caddisfly survival compared to the absence of a case. Campodeiform (elongated and flattened) larvae are found in aquatic habitats and are either free-living or net forming, whereas eruciform (caterpillar-like) larvae are case-bearing. dragonfly, Odonata, survival, Trichoptera, Three case types built by caddisfly larvae used in predation experiments. These insects are also called sedgeflies or railflies, they are small moth-like insects, having two pairs of hairy membranous wings. Future work should focus on the proximate mechanisms leading to reduced attack rate for these caddisflies, as well as the possible benefits of such a defense. Cases are made by gluing together with silk bits of plant or sand grains â sometimes even the shells of water snails â to camouflage and protect the soft-bodied larva from predators. Received 2011 Nov 18; Accepted 2012 Apr 16. However, previous studies have compared the survival of caddisflies with different cases, thereby precluding an analysis of the survival benefits of “weaker” case materials. He collected caddisfly larvae from the wild and put them in climate-controlled tanks. Nymphs of the dragonfly Anax junius Drury (Odonata: Aeshnidae) were used as the predator for this study. , The larvae of other species of caddisfly make nets rather than cases. Examining an organism's predator-prey interactions often provides insight into the causation of their behaviors and the evolution of morphological characteristics (Lima and Dill 1990). The larval stage lasts much longer, often for one or more years, and has a bigger impact on the environment. Caddisflies without a case were grasped for longer periods of time by dragonflies. , Nearly all adult caddisflies are terrestrial, but their larvae and pupae are aquatic. (A) “Leaf” case constructed by Agrypnia deflata. In another study using dragonfly nymphs (Aeshna juncea) as predators, the number of attacks, captures, and ingestions did not differ between caddisfly larvae with leaf cases and stick cases (Johansson and Johansson 1992). The aquatic larvae of caddisflies are famous for building portable, protective cases out of local materials, including grains of sand, bits of leaves and twigs, and other debris. For the no-case treatment, a species of caddisfly was randomly selected (all three species were equally represented) and the larva was gently removed from its case with a probe. They use small rocks, dirt, bits of wood and other organic matter they can find to make these cases and protect their fragile bodies. Caddisflies that had a case, regardless of material, were more likely to survive a predation event than individuals removed from their case (Figure 4). Caddisfly adults sometimes emerge in large numbers, often forming swarms. These net-making larvae usually live in running water, different species occupying different habitats with varying water speeds. Caddisfly larvae live underwater, where they make cases by spinning together stones, sand, leaves and twigs with a silk they secrete from glands around the mouth. When disturbed, it draws itself up within the house of sticks, mud and pebbles. Dragonfly nymphs were housed individually in round glass bowls (5 cm × 10 cm), with a small rock (approximately 2-cm diameter) for perching, and 225 mL of filtered tap water.  Some species indicate undisturbed habitat, and some indicate degraded habitat. The cases may be much larger and heavier than the larva itself (e.g., Otto 2000; Gall et al. Many caddisfly larvae build beautifully intricate cases from substrate particles of sand, small stones, leaf fragments, and the like and are highly specific to types of substratum (cf. Three species of caddisfly were used in this experiment, each constructing their case from a different material (Figure 1). Integripalpian larvae construct a portable casing to protect themselves as they move around looking for food, while Annulipalpian larvae make themselves a fixed retreat in which they remain, waiting for food to come to them. Stick cases (mean diameter ± SE = 7.49 ± 0.27) were wider than leaf (mean diameter = 3.64 ± 0.09) and rock cases (mean diameter = 4.32 ± 0.30). A trial ended after the caddisfly was ingested or after 10 minutes. This study investigated whether the presence of a case, of any material, offers protection against predators. Proportion of caddisfly larvae with one of four case types that survived predatory encounters with Anax junius nymphs. Furthermore, even cases constructed from materials generally assumed to provide less protection can provide a survival benefit to their occupant against some predators. A fourquadrant grid was placed beneath the dish, and the number of lines crossed by each caddisfly was counted as it moved across the dish. A useful reference to the larvae of the British Trichoptera is "Caddis Larvae" Norman E. Hickin (1967) Hutchinson & Co. Ltd. London. High quality figures are available online. In this study, several cased caddisflies were ingested, and in each instance the dragonfly required a substantial amount of time to consume the larvae. Each type has its own angling name, so for example Mystacides is the dancer; Sericostoma the caperer; Leptocerus the silverhorn; Phryganea the murragh or great red sedge; Brachycentrus subnubilis the grannom; Lepidostoma the silver sedge; Oecetis The latter two characters have undergone such extensive differentiation among the different superfamilies that the differences between the suborders is not clear-cut. Cummins, 1964; Cummins and Lauff, 1969; Mackay and Wiggins, 1979; Wallace and Merritt, 1980). Habitats can include streams, both cool and warm, lakes, marshes, and ponds. Artwork with caddis fly larvae and precious metals!  Adults are usually short-lived, most being non-feeders and equipped only to breed. The most common caddisflies, particularly in garden ponds, are the Cinnamon Sedges - a group of around 30 species. A caddisfly with the correct case type was randomly selected and removed with forceps from the appropriate tub. The cases provide protection to the larvae as they make their way between these resources. However, Nislow and Molles (1993) found that caddisflies were more likely to survive attacks against dragonflies (Oplonaeschna armata) when their cases contained a higher proportion of mineral material, although the authors interpreted this result with caution because the proportion of mineral material was assigned visually. They hold their wings above their body in a roof-shape when at rest. , Caddisfly cases are open at both ends, the larvae drawing oxygenated water through the posterior end, over their gills, and pumping it out of the wider, anterior end. Although stick-case caddisflies had similar survival compared to the other case types, they were attacked and captured less frequently. In addition, larvae with stick-cases experienced fewer attacks and captures by dragonflies. Some of the finest craft-skilled caddis larvae use carefully cut pieces of plant material to make their cases. Caddisflies with stick cases received fewer attacks and fewer captures than caddisflies with rock, leaf, or no case (Figure 2). There are 199 British and Irish species of caddisfly of which 3 have only been recorded in Ireland.  The land caddis, Enoicyla pusilla, lives in the damp litter of the woodland floor. A. deflata (henceforth “leaf-case”) were collected 24 August 2011 from a pond near Preston, Idaho.  The ancestors of all these groups were terrestrial, with open tracheal systems, convergently evolving different types of gills for their aquatic larvae as they took to the water to avoid predation. Mean (± SE) number of attacks (A) and number of captures (B) by Anax junius nymphs on caddisflies with one of four case types. Adult caddisflies are moth-like insects which generally fly at night. Female caddisflies lay masses of eggs on vegetation just above the water surface. As the larva grows, more material is added at the front, and the larva can turn round in the tube and trim the rear end so that it does not drag along the substrate. The results of our study demonstrate that the presence of any case, constructed from even relatively weak materials, provides protection from at least some predators. , Caddisflies are best known for the portable cases created by their larvae. He removes the larvae from their original cases and adds precious and semi-precious items into the tank. A larger number of summer species make cases from mineral resources as compared with autumn species which show a predominance of organic cases fashioned from fallen leaves (Otto, 1980). When pupating, species that build portable cases attach them to some underwater object, seal the front and back apertures against predators while still allowing water to flow through, and pupate within it. Members of the Psychomyiidae, Ecnomidae and Xiphocentronidae families construct simple tubes of sand and other particles held together by silk and anchored to the bottom, and feed on the accumulations of silt formed when suspended material is deposited. The effect of case type (no case, leaf, stick, or rock) on the number of attacks, number of captures, time spent grasping prey, and caddisfly activity (number of lines crossed) was assessed using a one-way ANOVA in a completely randomized design. The fish acquire them by two means, either plucking them off vegetation or the stream-bed as the larvae move about, or during the daily behavioural drift; this drift happens during the night for many species of aquatic larvae, or around midday for some cased caddisfly species, and may result from population pressures or be a dispersal device. Hydroptilidae, or open at both ends (called saddle cases) i.e. The results of our study demonstrate that the presence of any case, constructed from even relatively weak materials, provides protection from at least some predators. Often times the identity of a larval caddisfly can be determined just by looking at its' case. The adults are mothlike. Adult caddisflies are mothlike. To do this, the small, slow-moving creatures excrete â¦ The number of lines crossed was recorded during a five minute interval. Larva of caddis-fly in case of sticks con- structed by itself as protection against its enemies.