Tetralicia sawyeri, Valencia & Evans, 2024

Valencia, Luis & Evans, Gregory A., 2024, Review of the genus Tetralicia (Hemiptera: Aleyrodidae) and description of two new species of whiteflies found on avocado trees in Peru, Zootaxa 5403 (2), pp. 197-238 : 225-226

Tetralicia sawyeri n. sp.

( Figs. 1C–1D ; 7–8 )

Diagnosis.

Tetralicia sawyeri n. sp. is the only species in the genus that has all of its dorsal setae (Cs1, Ts2, Ts3, and Cas) very long, each one at least 3.5x as long as the vasiform orifice (vo); As8 about 2.7x vo length; the transverse molting suture extending to the lateral margin and the posterior region of the floor of the vasiform orifice with a row of 4 roundish structures. It is most similar to T. granulata which also has an undeveloped caudal protuberance and similar shape and chaetotaxy but can be distinguished from the latter species which has the Ts2 and Ts3 setae very short and the surface of the dorsum granulated, whereas in T. sawyeri , the dorsum is smooth to slightly rugose.

Description.

Puparium⸺In nature the puparia of T. sawyeri are shiny black in color, oval, covered by a layer of powdery white wax. The nymphs of the early stages are transparent yellow ( Figs. 1C, 1D ), while the nymphs of the third instar are shiny black in color with a faint band of whitish wax on the basal edge of the body. Slide specimen⸺ Body: Puparium ( Fig. 7 ) oval shaped, 1.6x as long as wide, true margin with dentate teeth ( Fig. 7C ), teeth not modified at the caudal and thoracic tracheal openings; each side deflexed under the body about 0.3x the radius of the body; caudal margin slightly protruding distally. Cephalothorax ( Fig. 7E ) with a zipper-like longitudinal suture (ls) extending from the anterior margin of the body to 0.5x the body length; transverse molting suture (tms) extends to the submargin region of the body, distally curving upwards; 3 pairs of long and stout setae, 1 pair each on the submedial region of the cephalus (Cs1), mesothorax (Ts2) and metathorax (Ts3), each 3.7x as long as the length of the vasiform orifice. The length of the setae vary, it is common to find in the same colony individuals with well-developed ones, where the cephalic and those of the eighth abdominal segment surpass the anterior and posterior margins of the body, respectively, but in other cases are short. Submargin with a row of submarginal setae (sms) and 17 geminated porettes with a group of 4–6 bright pores present on the submarginal region at the level of the mouthparts; medial and submedial region with dispersed geminate pores. Abdomen ( Fig. 7F ) as long as the cephalothorax with smooth, sclerotized, submedial abdominal depressions on segments 1–7 and with scattered geminate pores/porettes; of these, one pair is located in the submedial region of each segment, except for on abdominal segments 2 and 6, which have 2 pairs of geminate pores/porettes in the subdorsal region; submedial region of abdominal segments 4 and 5 each with a pair of closely associated bright pores; medial length of abdominal segment 7 about 0.75x as wide as that of segment 6; posterior margin slightly protruding; eighth abdominal segment setae (As8), about 2.7x as long as the length of the vasiform orifice; caudal setae long and stout, 3.7x as long as the length of the vasiform orifice. Vasiform orifice ( Figs. 7D, 7G–K ) cordate, 1.1x longer than wide, surrounded by a sclerotized rim; operculum cordate, 1.1x longer than wide, almost entirely filling the vasiform orifice with a few surface striations; lingula included with 4 strongly chitinized projections in the form of fingers at its apex. Venter: thoracic furrow not evident, antennae arising from the inside margin of coxae I; legs without spines or setae.

Adults ( Fig. 8 )

The adults of Tetralicia sawyeri have entirely white wings, very similar to those of adults of Bemisia tabaci (Gennadius) . The females and males are similar in size, shape and color, but like other aleyrodines, the females can be distinguished from the males by having 2 pairs of wax plates on their abdomen and an ovipositor whereas the males have 4 pairs of wax plates on their abdomen and an aedeagus and claspers. Adult female and male antennae are similar in characteristics, 7 segmented ( Figs. 8B, 8C ) with an elongate third segment (F3) having 2 primary round sensoria (rs) located near the distal apex and a long rod-like sensorial cone (sc) located on the apical third of the segment; F4 without sensoria; F5, F6 and F7 each with 1 round primary sensorium located at its apex of the segment. Chaetotaxy of tibiae 1, 2 and 3 are shown in Figs. 17–19, respectively. Hind tibia ( Fig. 8F ) with a tibial comb (tc) of about 18 setae, tibial brush (tb) with 2 setae; female genitalia ( Figs. 8G–8H ) normal, cement gland long, slender, tube-like with 3 shallow undulations along its ventral margin and 2 shallow dorsal undulations, one each between the ventral undulations, head mushroom-like.

Biology.

This species is the most widely distributed in Peru of the two species treated herein. Puparia are found usually scattered on the underside of the creole avocado leaves ( Fig. 1 ). However, in the months of autumn and winter (from mid-March to July), very dense colonies can be found on neglected trees especially in those that present “suckers” (undesirable buds that occur in the lower part of the trunk). The species was present in the two collection sites, presenting a higher incidence in Malpica Park. The area of the leaf where the nymphs of this species feed tend to show a characteristic discoloration ( Fig. 1D ) probably in response to the toxins injected by the nymphs in their feeding process. This phenomenon of the discoloration of the feeding area of the nymphs usually occurs with greater intensity in creole avocado trees of some varieties and not in others, especially in trees with thin leaves without much pubescence. As observed during the study of almost 8 years, this species and Aleuroplatus martini do not reach populations of economic importance and have a group of highly efficient natural enemies that regulate their population. In Malpica Park, T. sawyeri usually occurs in mixed infestations together with Aleurodicus juleikae Bondar, 1923 and Paraleyrodes bondari Peracchi, 1971 . In the El Bosque club, it also shares the avocado leaves with Aleuroplatus martini . Based on our study of 146 specimens of Tetralicia sawyeri , the vasiform orifice shows no indications of the existence of a structure like the traditional lingula in whiteflies. However, the quality of the preparations allowed the observation of the internal structures of the vasiform orifice by focusing at different depths of field ( Figs. 7 GK). The operculum in whiteflies is somewhat like a catapult in that it “flicks off” material excreted through the gut. The muscles ( Fig. 7I ) responsible for the up and down movement of the operculum form an inverted cup ending in a circular opening that fits with the base of the chitinous structure ending in the 4 finger-shaped projections. Although it is very unusual that the lingula would terminate in projections such as these, similar modifications of the lingula are known to occur and therefore this research assumes that these projections are part of the lingula.

Material examined.

Holotype puparium, Peru, Lima, Malpica Park , on Persea americana , slide with 13 puparia (holotype specimen marked inside a red circle), 14/vi/2015, L. Valencia, deposited in the NHM . Paratypes: numerous puparia on seven slides, same data as holotype, except collection dates 22/iv/2016; 02/i/2017; 21/05/2015; 22/iv/2016; 02/i/2017; 21/v/2015; 14/viii/2015; of these, one paratype slide each will be deposited in the USNM and UNALM, and the remainder of specimens in the first author’s collection . Paratypes are also highlighted on the slide with a red circle.

Etymology

This species is dedicated to the memory of Dr. Richard Sawyer, who was co-founder and first Director General of the International Potato Center in Lima, Peru.

Figures

FIGURE 1. A) Creole avocado trees in El Bosque club. Panoramic view of six trees (see arrows), showing differences in size, age and phenological status. While some are in the process of maturing fruits, others are beginning to flower and others are in the process of flowering and fruit set. B) generation of new Creole avocado trees in a ditch edge from seeds thrown by the club members, C) Tetralicia sawyeri n. sp. puparia on avocado leaves, D) detail of puparia on leaf, E) yellow coloration response of the avocado leaf around the body of nymphs and puparia of T. sawyeri n. sp., F) puparia of Aleuroplatus martini n. sp. on avocado leaves showing typical rods of yellow sulphureous wax on the underside of a leaf of creole avocado, G) detail of puparia with a drop of liquid above the waxy secretion, H) adults of Tetralicia sawyeri n. sp. on leaf.

FIGURE 7. Tetralicia sawyeri n. sp. puparium. A) habitus drawing, B) habitus slide mounted specimen, C) lateral margin (tm=true margin), D) vasiform orifice, E) cephalothorax (sms=submarginal setae; gp=geminate pores, cl=cluster of bright pores, F) abdomen (ad=abdominal depression, gp=geminate pores, bp=bright pores, G–K) vasiform orifice (vo) showing lingula with strongly chitinized, four finger-like projections at its apex and views at different depths of field, showing the muscles responsible for the movement of the operculum (op).

FIGURE 8. Tetralicia sawyeri n. sp. A) adults on avocado leaf; B–H) adult female: B) antenna, C) antenna, F3–F7 =flagellar segments 3–7, rs=round sensoriae, sc=sensorial cone, D) tibia I, E) tibia II, tb=tibial brush, F) tibia III, tc=tibial comb, G) ovipositor, ov=ovipositor, H) cg=cement gland.