Life history differences of P silotreta locumtenens ( T richoptera: O dontoceridae) in two reaches of a mountain stream in K orea

• Published in: Entomological research 2014-11, Vol.44 (6), p.293-301
• Main Authors: Seo, Ye Ji, Kim, Dong Gun, Baek, Min Jeong, Bae, Yeon Jae
• Format: Article
• Language: English
• ISSN: 1738-2297; 1748-5967
• DOI: 10.1111/1748-5967.12081

The life history traits of the caddisfly, P silotreta locumtenens   B otosaneanu ( O dontoceridae), were studied in two stream reaches with different thermal ranges (main and branch streams) of the G apyeong Stream, a typical mountain stream located in the central K orean P eninsula. P silotreta locumtenens larvae were quantitatively sampled monthly from N ovember 2008 to J uly 2010, and biweekly during the emergence period (late A pril to early J uly), using a Surber sampler (30 × 30 cm). Adults were quantitatively sampled with a sweep net. Larval density in the main stream (324.21 ± 38.59 m −2 ) was higher than that in the branch stream (60.48 ± 10.86 m −2 ). The larvae hatched in the early summer and overwintered as 5th and 3rd instars in the main and branch streams, respectively. The emergence peak at the main stream was approximately 2 weeks earlier. The sex ratio at both sites was approximately 0.3. The life history in both streams was univoltine. Secondary production in the main stream was much higher than in the branch stream, owing to high larval densities, and the P / B ratios at the two sites were similar. This study demonstrated remarkable differences in larval growth patterns and emergence peaks in P.  locumtenens between the two stream reaches due to differences in accumulated degree days (230.30 DD ) and other phenological cues such as daily mean threshold water temperature (9°C) during the ascending phase, despite their relatively small mean annual water temperature difference of 0.58°C.