Pachyschelus nicolayi

Distinguished from Pachyschelus purpureus by: (1) smaller body size, (2) absence of pubescent spotting on the elytra (P. purpureus has distinct pubescent spotting), and (3) later seasonal activity period. Distinguished from P. laevigatus by blue coloration versus black, and presence in different host plant associations. The combination of blue color, lack of pubescence, and association with Apios americana or Wisteria frutescens provides reliable field identification.

Small, blue metallic beetle without pubescent spotting. Slightly smaller than P. purpureus. Adults exhibit the characteristic flat, compact, wedge-shaped morphology typical of the tribe Trachyini, adapted for leaf-mining habits. The lack of pubescent spotting distinguishes it from the similar P. purpureus, which has such markings.

Associated with habitats supporting its larval host plants: Apios americana (groundnut), a perennial vine of wet meadows and stream banks, and Wisteria frutescens (American wisteria), a climbing vine of forests, woodlands, and disturbed areas. Adults have been observed on host plant foliage.

North America. Specific records include the northeastern United States; potentially occurs in Illinois though not yet formally recorded there. The species' range appears to overlap with that of its host plants Apios americana and Wisteria frutescens.

Adults active later in the season than P. purpureus, which is restricted to early spring. Based on host plant phenology and comparison to congeners, adult activity likely occurs from mid-summer through late summer.

• Apios americana - larval hostgroundnut; larva mines leaves
• Wisteria frutescens - larval hostAmerican wisteria; larva mines leaves

Larvae are leaf miners within leaves of host plants (Fabaceae), a characteristic of the tribe Trachyini. Adults feed on host plant foliage. Specific details of egg deposition, larval development duration, pupation site, and number of generations per year are not documented.

Adults feed on leaves of host plants. Larvae mine within leaves, creating characteristic feeding galleries. The species appears to be univoltine with a single adult generation, in contrast to the potentially bivoltine P. purpureus.

Leaf-mining larvae may influence host plant physiology through tissue removal, though specific impacts are unstudied. As a member of the tribe Trachyini, represents a derived ecological strategy within Buprestidae associated with herbaceous and woody legumes rather than wood-boring.

No known economic or agricultural significance. Potential interest to entomologists and naturalists due to its specialized host associations and as a subject for faunistic surveys. Not known to be a pest of cultivated Wisteria.

• Pachyschelus purpureusSimilar blue coloration but larger with distinct pubescent spotting on elytra; restricted to wild geranium (Geranium maculatum) as larval host; active only in early spring; allopatric host use prevents confusion with practice
• Pachyschelus laevigatusSimilar size but black rather than blue, lacks pubescent spotting; restricted to Lespedeza as larval host; allopatric host use and color difference allow separation

• Buprestidae
• Trachyini
• leaf miner
• Fabaceae
• Apios
• Wisteria
• metallic wood-boring beetle
• North America

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Brachys on oak | Beetles In The Bush
• Some recent publications | Beetles In The Bush
• Buprestidae | Beetles In The Bush | Page 6
• Berberidaceae | Beetles In The Bush