Furniss Malcolm M, Kegley Sandra J
Moscow, ID.
USDA Forest Service, Coeur d'Alene, ID.
Environ Entomol. 2018 Aug 11;47(4):775-780. doi: 10.1093/ee/nvy058.
The twig beetle, Pityophthorus pulchellus tuberculatus Eichhoff, infests dead branches of pines in western United States and Canada, including lodgepole pine, Pinus contorta Douglas, in northern Idaho. Adult broods overwintered in their host and emerged and colonized new hosts in late April. Males initiated galleries and were joined by up to seven females, each of which constructed an egg gallery radiating from a central chamber. Galleries had an average of 4.7 egg niches each with an egg that was large relative to the mother beetle. Two larval instars were recognized. Dentition of larval mandibles differed in shape from that in literature. Mature larvae pupated either in a cell excavated on the wood surface or in a cell below the wood surface. First-generation adults mined extensively in the inner bark and wood before emerging to infest new trees in late June. Their progeny became adults beginning in early August and likewise mined and fed on the inner bark and wood before overwintering. Predacious beetles present as larvae in the galleries included Enoclerus lecontei (Wolcott) (Coleoptera: Cleridae) and Lasconotus sp. (Coleoptera: Zopheridae). Parasitoid Hymenoptera reared from infested trees were Cosmophorus pityophthori Rohwer (Braconidae), Phasmidiasta n. sp. (Braconidae), Spathius sp. (Braconidae), Acerocephala n. sp. (Pteromalidae), Metacolus fasciatus Girault (Pteromalidae), Rhaphitelus maculatus Walker (Pteromalidae), Rhopalicus sp. (Pteromalidae), and an unidentified pteromalid.
细枝小蠹虫，即Pityophthorus pulchellus tuberculatus Eichhoff，侵害美国西部和加拿大松树的枯枝，包括爱达荷州北部的扭叶松（Pinus contorta Douglas）。成虫在寄主上过冬，于4月下旬羽化并迁移至新寄主上。雄虫开始筑造虫道，最多可有7只雌虫加入，每只雌虫都从中央腔室向外辐射状地建造一条产卵虫道。每条虫道平均有4.7个卵龛，每个卵龛中的卵相对于母虫来说都很大。识别出两个幼虫龄期。幼虫上颚的齿列形状与文献记载不同。成熟幼虫要么在木材表面挖掘的小室中化蛹，要么在木材表面下方的小室中化蛹。第一代成虫在6月下旬羽化前，在韧皮部内层和木材中广泛蛀食，之后去侵害新树。它们的后代从8月初开始羽化为成虫，同样在韧皮部内层和木材中蛀食和取食，然后过冬。在虫道中以幼虫形式存在的捕食性甲虫包括勒孔特埃诺叩甲（Enoclerus lecontei (Wolcott)，鞘翅目：郭公甲科）和Lasconotus属（鞘翅目：扁甲科）。从受侵害树木中饲养出的寄生性膜翅目昆虫有蠹小蠹科斯莫黄蜂（Cosmophorus pityophthori Rohwer，茧蜂科）、新种Phasmidiasta（茧蜂科）、斯氏茧蜂属（Spathius sp.，茧蜂科）、新种Acerocephala（金小蜂科）、具带后缘金小蜂（Metacolus fasciatus Girault，金小蜂科）、黄斑长尾金小蜂（Rhaphitelus maculatus Walker，金小蜂科）、喙棒金小蜂属（Rhopalicus sp.，金小蜂科）以及一种未鉴定的金小蜂科昆虫。
