Patia rhetes (Hewitson, 1857)

Castro-Gerardino, Diana Jimena & Llorente-Bousquets, Jorge, 2019, Antennal ultrastructure in Patia (Pieridae, Dismorphiinae), Zootaxa 4559 (3), pp. 445-472 : 450-451

Patia rhetes (male)

ANTENNAL CLUB ( Figs. 2a , 3a, m, n ): The nudum measures around 2.6 mm.

ANTENNOMERES ( Figs. 3 a–d, m–o): There are 11 or 12 scaleless antennomeres although the first basal has scales in the dorsolateral area and the proximal margin of the ventral surface; occasionally, the scaleless area invades the previous segment on its ventral surface. The first segment of the nudum is isometric or depressed and the following segments (second to ninth) are depressed while the distal one is compressed. The l/w ratio is 0.6–0.9 in the first antennomere, 0.5–0.7 in the second, 0.5–0.6 from the third to ninth or tenth, and 1.4–1.8 in the distal. The scaleless antennomeres are cylindrical (first antennomere), doliform (from the second to the ninth) and digitiform with the acute apex (the distal fused). Sometimes, the distal antennomere has three fused segments.

SULCI AND PSEUDOSULCI ( Figs. 3 b–e, g, o): With 10–12 central sulci and 16–22 lateral ones. The antennomeres from the second to the fourth are trisulcate. The central sulci are present in almost all the antennal segments and occupy one-third to one-half of the length of the antennomere and between one-third and one-fifth of its width. In all cases, the central sulci are close to the distal margin of the antennomere; sometimes this margin truncate the sulci, or they are separated by two or three rows of microtrichia m2. In the proximal and some mesial segments (first to sixth), the central sulci are irregular and elongated with discontinuous edges while in the other antennomeres, they are elliptical and continuous; or in all the antennomeres the central sulci are elliptical and continuous. The lateral sulci are smaller than the central ones and occupy a third or less of the length of the antennomere; in the proximal segments, they are smaller, but their size increases in the medial and distal segments. Two or five rows of microtrichia m2 separated them from the distal margin of the antennomeres; only in the distal segments, the lateral sulci are truncated (from the eighth to the tenth). In the proximal antennomeres (from the first to the third), they may be absent, and in their place, there are small pseudosulci, but sometimes none. In almost all antennomeres the lateral sulci of the left side (ventral view) are larger than those of the right. Although it is not usual, sometimes in some distal antennomere, one of the lateral sulci appears disintegrated into two or three large pseudosulci. The lateral sulci are rounded or elliptical, and their edges are continuous. The pseudosulci are present in almost all the antennomeres of the nudum and are abundant in some specimens (up to eleven in a segment) and scarce in others (maximum of three in a segment); they are abundant in specimens with dark nudum and scarce in those with yellow nudum (see discussion). They abound where the lateral sulci are absent, and the central ones have an irregular contour. Most often the small pseudosulci (1 to 4 st) are circular, or elliptical and the large ones (over 5 st) are irregular and elongated. In the first antennomere, the pseudosulci are near the distal margin or next to some lateral sulcus; in following proximal segments its number increases, and along the nudum they merge with the closest sulci. The smallest ones are under the central sulcus or close to the proximal margin of the antennomere; the largest ones (up to 9 st) are next to the lateral sulci or in place of these. In clubs with few pseudosulci, usually, these are between the lateral sulci and the central, toward the middle or near the distal margin of the antennomere. In the distal fused segment, the pseudosulci are few or absent.

MICROTRICHIA ( Figs. 3f , h–j): There are microtrichia types m1-m4. The st:m1 ratio in the central sulci is 1:2. In the lateral sulci, this proportion is 1: 2 in the proximal and medial antennomeres; in the distal, it is 1:3 or 1:4.

TRICHOID SENSILLA ( Figs. 3e, f ): The trichoid sensilla measure on average 19.7 µm (n = 10; 14.9–24.4 µm). The st presents in the pseudosulci are shorter and have an average length of 14.7 µm (n= 10; 10.3–18.1 µm). Among the third and fifth antennomere, the number of trichoid sensilla reaches its maximum and descends along the nudum. The sensilla in the lateral sulci reach their greatest number in the fifth antennomere where is the largest lateral sulcus. In the segments where the pseudosulci are abundant, the number of st in the central sulci is smaller; when summing the number of sensilla in the pseudosulci and those in the central sulcus, the result is a similar number than sensilla in equivalent antennomeres, but with few pseudosulci or none. The above corroborates the aggregative character of the pseudosulci.

CHAETIC SENSILLA ( Fig. 3h ): The average length is 41.3 µm (n= 9; 30.3–52.9 µm). Its location is characteristic of the subfamily, except in the first antennomere of the nudum, where the sulci are irregular, or there are only pseudosulci. The majority of this sensilla are close to the distal margin of the antennomere; when the sulci have a discontinuous contour, the chaetic sensilla are close to the perimeter of the central sulcus.

OTHER SENSILLA ( Figs. 3 i–l, p): The other sensilla in the antennal club are less abundant in the proximal antennomeres and along the nudum their number increases. The basiconic sensilla predominate outside the sulci and pseudosulci; its number is about ten times greater than other sensilla such as auriculate and coeloconic. The auriculate sensilla (sa) are on the edges of the central and lateral sulci. The coeloconic sensilla (sc), although scarce, are present from the first antennomere near the sulci, frequently the lateral ones. The styloconic sensilla without stylus (sty) are present at the apex of the distal fused segment and, sometimes, near to lateral sulcus in the mesial antennomeres. A single unidentified sensillum occurs in the distal margin of the sixth antennomere ( Fig. 3l ).

Figures

FIGURE 2. Diagram of the antennal club of Patia rhetes (male). a. Antennal club and nudum with 12 scaleless antennomeres; scales cover part of the basal or proximal segment; b. Parts of a medial antennomere: central sulcus (Sc), left lateral sulcus (Sll), right lateral sulcus (Slr), pseudosulcus (Ps), chaetic sensillum (sq) and length (l) and amplitude (w) used in the l/w ratio that measures the depressed or compressed antennomeres; c. Central sulcus with trichoid sensilla (st) and microtrichia m1 and m2.

FIGURE 3 (a–f). Antennal microstructures in Patia rhetes male (yellow antennal club). a. Scaleless antennal club; b. Scales cover partially the first antennomere of the nudum and two pseudosulci are instead of the central and left lateral sulci (x250); c. Distal antennomere (fused) with two central sulci (arrows) (x200); d. Fifth antennomere of the nudum; left lateral sulcus and central sulcus, among which is a pseudosulcus (arrow) (x250); e. Central sulcus of fifth antennomere (x800); f. Trichoid sensilla of sulcus central surrounded by microtrichia m1 (x3.5 k).