Life history, growth patterns and feeding habits of two predatory stoneflies, Skwala pusilla (Perlodidae) and Kamimuria tibialis (Perlidae) in northern Japan

• Published in: Aquatic insects Vol. 30; no. 1; pp. 29 - 41
• Main Authors: Otsuki, Akiko, Iwakuma, Toshio
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 01.03.2008
• Subjects: algae; carnivory; Kamimuria; Perlidae; Perlodidae; Plecoptera; Skwala; univoltine; Japan
• ISSN: 0165-0424; 1744-4152
• DOI: 10.1080/01650420701827421

Life history, growth patterns and feeding habits were compared between two common predatory stream stoneflies, Skwala pusilla and Kamimuria tibialis. Both species are univoltine with the larvae appearing in the streams in summer and showing high growth rates in autumn. Skwala pusilla continued growing to the final instar during winter, and then emerged in early spring. In contrast, the growth of K. tibialis stagnated in winter and turned high again in spring when they molted to the final instar. Skwala pusilla consumed a higher proportion of algae than did K. tibialis, and a randomisation test indicated significant difference between the two species in the degree of carnivory. However, S. pusilla did not enhance the degree of carnivory in winter when the growth of K. tibialis stagnated. These results suggest that the relatively low degree of carnivory in S. pusilla is not due to interspecific competition for prey resources.