Zapatella petiolata Pujade-Villar & Caicedo n. sp.

Distribution

Colombia (department of Cundinamarca).

Gall Description

The galls are multilocular and inseparable from the plant tissue. They are located on the petioles of leaves (Figs. 5–7).

• Sizes range from small swellings (3–6 mm in length) to prominent enlargements (up to 25 mm in length and 12 mm in diameter), depending on the number of larval chambers (few to over 50 per gall).
• Larger galls are observed on oak morphotypes with denser tomentum.
• The surface is rough, and affected leaves discolor and necrotize (Fig. 5), due to the collapse of lateral vascular bundles in older galls after insect emergence.
• The resulting structure acts as a small aborted branch, often developing a new branch from the deformed petiole’s meristematic apex (Fig. 7b). This phenomenon is recognized as reiteration (Mora-Osejo, 1987; Perreta & Vegetti, 2005).

The new branches may produce leaves that can be attacked by subsequent generations of Zapatella. The larval chambers, measuring 2 × 1 mm, are located just beneath the thickened surface in a non-patterned arrangement (Figs. 6d, 7a).

Host

Collected exclusively on Quercus humboldtii (section Lobatae).

Biology

• Galls develop on petioles of young leaves, characterized by anthocyanin-rich meristems. As the gall matures, the meristem becomes chlorophyllous, and the leaves become leathery.
• Larval development lasts 14–18 months, depending on rainfall and ambient humidity. Prolonged droughts extend larval development.
• Adults emerge just before the rainy season, on sunny days.
• Emergence timing varied over three years: April 2015, July 2016, and January and April 2017.
• Emergence is synchronized, with larvae developing almost simultaneously.

In confined conditions, multiple specimens were exposed to seedlings with young reddish leaves (rich in anthocyanins), but no oviposition or gall formation was observed. This suggests the species does not reproduce via indefinite parthenogenesis. The sexual generation remains unknown but is hypothesized to develop in the acorns of Q. humboldtii, as a gradation in acorn development has also been observed (unpublished data).

Holotype:
The holotype female is deposited in IAvH with the following labels:

1. "Parque La Florida (Cota, Cundinamarca, COL), 4°43′47″N 74°09′00″W, 2613 m a.s.l., Q. humboldtii, (25.iv.2015) 25.iv–10.v.2015, leg. JP-V" (white label).
2. "Zapatella petiolata ♀ Pujade-Villar & Caicedo 2017, desig. JP-V 2015" (red label).

Paratypes (91 females):

• Same data as the holotype:
  • 12 ♀ (6 ♀ in IAvH, 6 ♀ in UB).
  • Same data, collected on (6.vii.2016) 7–15.vii.2016: 15 ♀ (10 ♀ in IAvH, 5 ♀ in UB).
  • Same data, collected on (15.i.2017) 15–31.i.2017: 61 ♀ (30 ♀ in IAvH, 17 ♀ in UB, 7 ♀ in USHM, 7 ♀ in AMNH).

Additional Paratypes:

• Same data as the holotype:
  • 6 ♀ (3 ♀ in UB for SEM).
  • Collected on (6.vii.2016) 7–15.vii.2016: 11 ♀.
  • Collected on (15.i.2017) 15–31.i.2017: 1626 ♀ (871 ♀ in IAvH, 155 ♀ in UB, 600 ♀ used for experimentation).
  • Collected on (23.iv.2017): 66 ♀ (56 ♀ in IAvH, 10 ♀ in UB).
  • Collected in May 2017: 118 ♀ (105 ♀ in IAvH, 13 ♀ in UB).

Other Locations:

• Los Robles, Albán (Cundinamarca, COL), 4°50′53.12″N 74°26′27.32″W, 2267 m a.s.l., Q. humboldtii, collected on (6.i.2011) 11.i.2011, only galls (leg. P. Rodríguez).
• Between the municipalities of La Calera and Guasca (Cundinamarca), collected on (9.ii.2017), only galls (leg. A. González).