Hungerford's Crawling Water Beetle

Hungerford's crawling water beetle, like all beetle species, undergoes complete metamorphosis with a life cycle that consists of four distinct stages - egg, larva, pupa, and adult. The pupal stage is the only one spent in a terrestrial setting. Mature larvae leave the water in search of a place in damp sand to pupate.

Reproduction usually occurs in the spring and early summer. Mating has been observed in June for Hungerford's crawling water beetle. Adults of Hungerford's crawling water beetle have been found year round, suggesting that some adults survive the winter, even beneath ice cover. Other species in the Haliplidae, the family of crawling water beetles, have at least one generation in the summer and likely another in the late summer or fall. Observations of Hungerford's crawling water beetle in the East Branch of Maple River suggest that they may have two generations per year, with adults emerging in early spring, during May, and a second brood of adults emerging late in the season, in August.

Adults appear to be generalists in their food choice, feeding on algae including Chara, Cladophora and Dichotomosiphon, as well as the epiphytic diatom Cocconeis. The diet of adults may also change seasonally. Larvae appear to prefer the alga Dichotomosiphon tuberosus. Dichotomosiphon, although widespread, is not common. Its presence may be an important factor in determining the distribution of Hungerford's crawling water beetle.

Adult haliplids are generally not fast or strong swimmers and spend the majority of their time crawling on the bottom among the cobbles and aquatic vegetation. It is unknown how Hungerford's crawling water beetles disperse within the stream. Drift is a possible mechanism of dispersal. They may also be able to crawl upstream to colonize new sites. It is not known to what extent these beetles use drift or what distances they can crawl upstream. Another potential mechanism of dispersal is flight. Adults of most aquatic Coleopteran species leave the water on dispersal flights, although flight in this species is not observed. It is unknown whether they are capable of utilizing flight as a means of dispersal to distant suitable habitats.

Populations of this species are found downstream from culverts, dams that are made by beaver and other natural debris dams and human-made impoundments. They are found in plunge pools which are created below these structures, as well as in riffles and other well-aerated sections of the stream. In general, this species is found in areas of streams which are characterized by moderate to fast stream flow, good stream aeration, inorganic substrate and alkaline water conditions. The adult beetles are generally found at depths of a few inches to a few feet in streams that are relatively cool, with temperatures between 15º to 25º Celsius. The hydrology of a site appears to be important for this species. These beetles seem to prefer seasonal streams that have some groundwater input. These streams do not dry up completely, but the water level can drop considerably. For example, several feet in the East Branch of the Maple River. As the water levels drop, damp river edge sand becomes exposed in the summer and fall. This microhabitat may be important for the pupation stage of the life cycle.