|scientific name Trypodendron |
common name Ambrosia beetles
Of the tribe Xyloterini, family Scolytidae. Length 2.7 – 4.6 mm. Colour brown to black or bicoloured. Variation in sex is seen in size, color and sculpture. Members of this genus are distinguished by the strongly procurved basal area of the antennal club, subquadrate male pronotum, externally deeply concave frons in males and dimorphic convex frons of females. Females usually larger than males probably due to the shortened pronotum in males whereas it is sub circular in females. Frons of females have surface reticulated with sparse granules while in males they are with lateral margins ornamented by abundant hair (T. retusum, T. lineatum and T. rufitarsis, or with a median tubercle between upper halves of the eyes (T. betulae) (Bright, 1976; Wood, 1982).
Monogamous ambrosia beetles attacking weakened, unhealthy dying trees larger than 10cm in diameter. Entrance tunnels are formed by the female before the male arrives. The tunnels penetrate bark into sapwood or heartwood in different species and may branch multiple times. Eggs are laid in cradles where they develop into larvae. Larvae as they mature enlarge the cradles until they are big enough to accommodate the mature adult. The cradles also serve as the pupation chambers and the emerging adults exit the chambers through parental entrance (Bright, 1976; Wood, 1982).
All species (adults) of this genus bore into woody tissues either sapwood or heartwood of their host species. They introduce and maintain gardens of ambrosial fungus on which they and their larvae feed (Bright, 1976).
Canada; eastern and western United States and Eurasia (Bright 1976)
Comments are published according to our submission guidelines. The EH Strickland Entomological Museum does not necessarily endorse the views expressed.