Trichaetipyga infantilis ( Ball, 1937 )

Montalvo-Salazar, Jorge L., Rueda-Rodríguez, María P. & Torres Arizaga, David M., 2024, First records of the treehopper Trichaetipyga infantilis (Ball, 1937) in Ecuador with the description of its nymph and notes of natural history, and morphology, Zootaxa 5541 (1), pp. 89-94 : 90-92

Trichaetipyga infantilis ( Ball, 1937)

( Figures 1–3 )

Distribution: Mexico, Costa Rica, Venezuela, Colombia, and Ecuador (New Record) ( Fig. 4 ). We report here the southern-most records for the species, from the northern Amazonian lowlands and foothills of northwestern Ecuadorian Andes, around 620 km and 760 km. The species frequently inhabits lowlands below 700 m of elevation, however, Flórez-V. et al. (2015) have recorded the species from> 1800 m of elevation in the Colombian Andes.

Material examined: One nymph, two males and three females ( ZSFQ-i7928 , 9059,11131 , 17972 ) from Nueva Loja ( Sucumbíos ) [0.102022ºN 76.887272ºW, 300 m of elevation]; one male and one female (ZSFQ-i17711, 17712) from Santo Domingo (Santo Domingo de los Tsáchilas) [0.302838ºS 79.155478ºW, 500 m of elevation] .

Female genitalia description. Pygofer surface smooth and almost glabrous except for small setae on ventral surface around aperture ( Figs 2A, B ). Gonoplac apical half broad, gradually swollen, apex shortly rounded; dorsal margin straight, ventral margin more sclerotized, convex, and with macrosetae ( Fig. 2C ). First valvula curved upward, narrowing towards apex; ramus extending almost throughout valvula, dorsal sculptured area restricted in distal half with dense fine oblique integumental lines gradually increasing from the dorsal margin to ramus, ventral sculpted area restricted at apex with subperpendicular irregular integumental lines widely separated ( Fig. 2D ); apex acute and dorsal margin straight ( Fig. 2E ). Second valvula more sclerotized than first, curved upward, tapering apically, apex acutely rounded ( Fig. 2F ); apical fifth of dorsal margin irregularly serrate ( Fig. 2G ), apex finely serrate ( Fig. 2H ).

Nymph description ( Figs 1E, F , 3A ). Coloration. Pale yellowish with reddish bands or patches on the head, thorax, wing pad, legs, and abdomen. Overall body. Laterally compressed with long scoli with stalked chalazae on every segment; dense chalazae on head, between scoli, legs, and ventral margins of thoracic and abdominal tergites. Head. One pair of scoli longer than head height and obliquely directed forward; covered with large and simple chalazae. Prothorax. Pre- and postmetopidum each with pair of dorsal scoli, longer than head scoli and obliquely directed forward; pronotum with triangular posterior apex slightly curved upwards, hidden between mesothoracic scoli in lateral view and not surpassing mesonotum. Mesothorax. One pair of dorsal scoli obliquely directed forwards and as long as postmetopidum scoli; enlarged chalazae setae on ventral margin of forewing pad. Metathorax. Dorsally with paired scoli. Legs. Chalazae present from coxa to tarsus, enlarged on tibiae. Abdomen. Terga III–VII laterally glabrous with dorsal, subparallel scoli of subequal lengths, 8 or more x their basal widths; tergum IX scoli half-length of anterior tergal scoli and located apically; terga III–VIII ventrolateral margins each with 2 pairs of enlarged chalazae and dense small chalazae on ventral margin; segment IX in lateral view equal to combined lengths of segments V–VII, dorsal margin with 2 parallel rows of enlarged chalazae.

Few Ceresini nymphs have been described, including only some species from the genera Stictocephala , Spissistilus , Tortistilus , Stictolobus , and Ceresa . The nymphs of those genera and Trichaetipyga infantilis have dorsal spine-like scoli and stalked chalazae on the head, pronotum, and abdomen ( Quisenberry et al. 1978; Grosso et al. 2014; Wheeler & Rothschild 2020).

Natural history. This species inhabits pastures at the borders of water bodies or forests and is abundant in highly disturbed areas. Adults and nymphs are mainly solitary although, on one occasion, three adult individuals shared the same plant but did not feed on it. The nymph stayed in the stalk base of their host plants while adults usually in the high portion of the plant ( Figs 3A–C ). This behavior has been described in more detail for other Ceresine species, in which the emerged nymphs move to the base of the plant and gradually climb up while they grow and become more active ( Grosso et al. 2014; Khan et al. 2022).

Adults and the nymph were not attended by ants or other hymenopterans. We recorded T. infantilis on both dicots and monocots ( Table 1 ), although it was more frequently found in Paspalum sp. ( Poaceae ), which we suspect to be the main host plant because the nymphs have been only seen on that plant species and it was the most frequently seen plant association of the adults. Wheeler & Rothschild (2020) found the nymphs of another Ceresine, Stictolobus minutus (Funkhouser) , are specialized on a single species of Poaceae . Other Ceresine species have been observed to feed on grasses but mostly are recorded as polyphagous on dicots and monocots (Flórez-V. et al. 2015).

Remarks. Kopp & Yonke (1979) argued that Trichaetipyga infantilis varies in the relative development of the suprahumeral horns (see their Figs 43–48). The syntypes of this species ( United States National Museum of Natural History, available at http://n 2t.net/ark:/65665/3a2cc0b1f-e932-4087-9157-d76bd425ce21), have short suprahumeral horns, with those of the female slightly more pronounced than the male. In contrast, in all our speicmens the suprahumeral horns are strongly developed and acute in females and males ( Figs 1A–D ), as is the specimen illustrated by Flórez-V. et al. (2015) from Colombia (see Figs their 36A, 37D). Further studies might reveal that T. infantilis represents more than one cryptic species.

Figures

FIGURE 1. Trichaetipyga infantilis habitus. A. male in lateral view. Female: B. frontal view, C. lateral view, D. dorsal view. Nymph: E. frontal view, F. lateral view.

FIGURE 2. Trichaetipyga infantilis female. Abdomen: A. lateral view, B. ventral view. C. gonoplac in lateral view. First valvula: D. lateral view, E. close-up of anterior portion. Second valvula, F. lateral view, G. close-up of anterior portion, H. closeup of apex.

FIGURE 3. Trichaetipyga infantilis in its natural environment. A. nymph on stalk base of Paspalum sp., B. adult on spike of Paspalum sp., C. adult on a leaf of Ipomoea sp.

FIGURE 4. Distribution of Trichaetipyga infantilis. Red circle: type locality (Acapulco, México), yellow square with symbol “?”: doubtful records, blue triangle: new records from Ecuador, white squares: other records from literature.