Temperature effects on development and cuticular hydrocarbons in forensically relevant Dermestes maculatus

Area of Science:

• Forensic Entomology
• Chemical Ecology
• Insect Physiology

Background:

• Dermestes maculatus beetles are crucial in forensic science for post-mortem interval (PMI) estimation due to their presence on decomposing remains.
• Species-specific cuticular hydrocarbons (CHCs) on the beetle's cuticle vary with developmental stage, sex, and environment.
• Understanding larval age indicators is vital for accurate PMI determination.

Purpose of the Study:

• To investigate larval body size and CHC profiles as indicators of larval age in Dermestes maculatus.
• To assess the impact of controlled rearing temperatures (20°C, 30°C, 40°C) on larval development and CHC profiles.
• To determine the reliability of these indicators for forensic applications.

Main Methods:

• Adult Dermestes maculatus were collected, identified morphologically and genetically (mtCOI gene).
• Larvae were reared under controlled conditions (60% RH, 12:12 L:D) at 20°C, 30°C, and 40°C.
• Larval morphometrics (length, head capsule width, weight) and CHC profiles (GC-MS) were analyzed across instars.

Main Results:

• Developmental duration decreased with temperature from 20°C to 30°C; development arrested at 40°C.
• Larval size increased between 20°C and 30°C, with significant variations across instars.
• CHC profiles showed significant differences based on larval instar and rearing temperature.

Conclusions:

• Larval body size and CHC profiles are reliable indicators of larval age in Dermestes maculatus.
• Temperature significantly influences larval development, size, and CHC composition.
• Further validation under field conditions is necessary for routine forensic PMI estimation.