How to distinguish a female bed bug? - briefly
Female bed bugs are typically larger, with a broader, more rounded abdomen and a visible spermatheca near the posterior end; males have a narrower, pointed abdomen and no spermatheca. These morphological differences allow reliable sex identification.
How to distinguish a female bed bug? - in detail
Identifying a female Cimex lectularius requires careful observation of external morphology and reproductive status. Females are generally larger than males, measuring 5–6 mm in length compared to 4–5 mm for males. The abdomen of a female is noticeably broader and more rounded, especially after blood meals, whereas the male abdomen remains slender and tapered.
Key characteristics include:
- Abdomen shape: expanded, convex dorsal surface; male abdomen flat and narrow.
- Presence of an ootheca: adult females carry one or more eggs within the abdomen, visible as a pale, oval mass through the cuticle.
- Terminal segment: the female’s terminal abdominal segment (the ovipositor) is elongated and lacks the stylus found on males.
- Antennae and forelegs: both sexes possess similar sensory hairs, but the female’s forelegs are slightly more robust to support egg‑laying activities.
Microscopic examination enhances accuracy. Under 40–100× magnification, the female’s genitalia appear as a pair of curved spermathecae near the ventral sternite, while males display a distinct paramere. The presence of a visible egg mass confirms female status unequivocally.
Practical inspection steps:
- Collect specimens from suspected harborages (mattresses, cracks, furniture).
- Place each specimen on a white background and examine with a hand lens or stereo microscope.
- Measure body length; note abdomen width and curvature.
- Look for internal egg masses through the translucent cuticle.
- Confirm genital morphology by focusing on the terminal abdominal segment.
Accurate differentiation supports targeted control measures, as only females contribute to population growth through oviposition. Recognizing these traits eliminates misidentification and optimizes pest‑management interventions.