Aquatic insects and feeding ecology
Merritt specialises in the feeding ecology and biology of aquatic insects, particularly Diptera. This work connects identification with questions about food acquisition, habitats and ecological roles, making taxonomic knowledge useful for understanding aquatic communities.
References: [1]
From a course manual to successive editions
Merritt and Cummins first edited their aquatic-insect manual in 1978. Martin Berg later joined the editorial team, and a fifth edition appeared in 2019. Identification of immature and adult stages is complemented by ecological information and literature in individual chapters.
Insect records and environmental assessment
The manual covers distribution, tolerance values, trophic relationships and functional adaptations, including a chapter on biological assessment. Merritt also taught stream biomonitoring, connecting the collection and identification of organisms with ecological interpretation.
References: [1]
University and forensic entomology
Merritt served as chair of Michigan State’s Department of Entomology, conducted laboratory and field research, and supervised graduate students. His teaching also included forensic entomology, extending his work from aquatic ecology to applied insect science.
References: [1]