Pristiphora retusa (Thomson, 1871)

Prous, Marko, Kramp, Katja & Liston 1, Veli VikbergAndrew, 2017, North-Western Palaearctic species of Pristiphora (Hymenoptera, Tenthredinidae), Journal of Hymenoptera Research 59, pp. 1-190 : 59-60

Pristiphora retusa (Thomson, 1871) Figs 11, 41, 103, 134, 260

Nematus retusus Thomson, 1871: 109-110. Lectotype ♀ (NHRS-HEVA000003756; here designated) in NHRS, examined. Type locality: Dalarna, Sweden.

Similar species.

The most similar species is P. exigua , females of which have a completely pale metafemur (usually in most part black in P. retusa ) and a broader valvula 3. Males are best recognised by examining penis valves (see the Key).

Genetic data.

Based on COI barcode sequences, belongs to its own BIN cluster (BOLD:ABU7029) (Fig. 3). Maximum distance within the BIN is 0.3%. The nearest neighbour to BOLD:ABU7029, diverging by a minimum of 4.3%, is BOLD:ADD4067 ( P. exigua ). Based on nuclear data, maximum within species divergence is 0.3% (based on three specimens and NaK or both genes combined) and the nearest neighbour is 2.4% different [ P. bivittata (Norton, 1861), a Nearctic species, only NaK].

Host plants.

Prunus padus L. ( Benson 1954b, Kangas 1985, ex ovo rearing experiments by VV).

Rearing notes.

Ovipositing experiment no. 1/1978: Finland, South Häme, Janakkala, Hangastenmäki. On 22-23.V.1978 two captured females laid eggs into pockets on undersides of young leaves of Prunus padus . Larvae hatched on 27.V.1978, and ate holes into leaves. Four larval instars were observed, the development of larvae was rapid and on 7.VI.1978 prepupae were found. No extra moult after feeding.

Distribution and material examined.

Palaearctic. Specimens studied are from Germany, Russia (Primorsky Krai), and Sweden.