Extended-diapause
Guides
Curculio occidentis
filbert weevil, California Acorn Weevil
Curculio occidentis, the filbert weevil, is a weevil species native to western North America. It is primarily known as a seed predator of oak acorns, with documented infestations on Garry oak (Quercus garryana), coast live oak (Quercus agrifolia), and other oak species. The species has also been recorded feeding on hazelnuts (Corylus avellana), though it generally prefers endemic oak species and rarely causes economic damage to commercial hazelnut crops. Females lay small batches of 2-4 eggs in developing acorns; larvae feed on kernels and exit in autumn to pupate in soil, potentially remaining dormant for 1-2 years before adult emergence.
Curculio sayi
small chestnut weevil, lesser chestnut weevil
Curculio sayi is a true weevil (family Curculionidae) known as the small or lesser chestnut weevil. It is a highly host-specific pest of chestnuts in the genus Castanea, feeding and ovipositing exclusively on chestnut and chinquapin species. The species was historically a major pest of American chestnut (Castanea dentata) before the chestnut blight, with infestation rates of 50-75% considered normal. It has resurged as a significant pest with the restoration of blight-resistant chestnut plantings. Adults exhibit sexual dimorphism in body size and rostrum length, with females being larger and possessing longer snouts adapted for penetrating chestnut burrs.
Diabrotica barberi
northern corn rootworm
Diabrotica barberi, the northern corn rootworm, is a chrysomelid beetle native to North America and a major pest of corn (Zea mays). Larvae feed on corn roots, causing significant economic damage, while adults feed on corn silks, pollen, and leaves. Unlike the western corn rootworm, D. barberi has not developed resistance to Bt traits in Iowa as of 2019-2020 surveys. The species exhibits extended diapause in some populations, with eggs remaining dormant for multiple years before hatching. Research indicates its flight behavior differs from D. virgifera, with shorter but more frequent flights and less sustained long-distance movement.
Diprion similis
Introduced Pine Sawfly, Imported Pine Sawfly, White Pine Sawfly
Diprion similis is a conifer-feeding sawfly native to central and northern Europe and Asia that has become invasive in North America following its accidental introduction around 1914. The species is notable for its arrhenotokous reproduction, where unfertilized eggs develop into male offspring, facilitating rapid population establishment. Larvae are gregarious defoliators of pine needles, with a strong preference for white pine (Pinus strobus) in North America. The species exhibits two generations per year in many regions, with second-generation larvae overwintering as prepupae in cocoons. Its invasive success has been attributed to parthenogenetic capabilities, lack of natural enemies in introduced ranges, and specialized pheromone communication involving the (2S,3R,7R)-propionate isomer of 3,7-dimethylpentadecan-2-ol.
Psaphida
Psaphida is a genus of owlet moths in the family Noctuidae, established by Francis Walker in 1865. Species in this genus are primarily North American, with most distributed across the eastern and central United States and southern Canada. One species, P. palaearctica, occurs in Shaanxi, China. The genus includes early spring-emerging species such as Roland's Sallow (P. rolandi), which has been documented to exhibit extended pupal diapause lasting up to seven years.