We describe Aeolothrips romanruizi sp. nova that has been recently discovered in mango orchards in the Isthmus region of Oaxaca in southern Mexico. Aeolothrips romanruizi sp. nova exhibits an ornamentation of the mesonotum and metanotum very different from others in this genus, except A. microstriatus, which is similarly ornamented; but these 2 species differ in forewing color pattern, body size and some other characters of chaetotaxy. A key to the Aeolothrips species of Central America and Mexico is provided.
Insect predators are one of the most important agents in insect pest management practices, especially in those scenarios where there are few known parasitoids to control microarthropod pests (Sânchez-Ruiz et al. 1997). Predatory thrips species of Thysanoptera: Aeolothripidae have been studied as potential biological control agents. For example, Franklinothrips orizabensis Johansen 1974 has received much attention as a possible biological control agent of thrips species that are harmful to crops (Hoddle 2003b).
Members of Aeolothripidae are medium-sized, usually with dark brown bodies about 2.5mm long (Mound & Marullo 1996). Adults and larvae of many species in this family appear to be facultative predators of other small arthropods, in that they feed on both floral tissues as well as on thrips and mites that live in flowers. Some species are almost certainly exclusively phytophagous (Tyagi et al. 2008), but in the warmer parts of the world, a considerable number of species are predators (Hoddle 2003a). Worldwide, about 250 species are recognized in 26 genera of Aeolothripidae (Mound & Marullo 1996).
Studies in avocado groves in search of natural enemies of Scirtothrips perseae Nakahara 1997 have identified predator species in Aeolothrips, Aleurodothrips, Franklinothrips, Leptothrips, Scolothrips, and Karnyothrips as possible biological control agents (Hoddle et al. 2002; Cambero-Campos et al. 2011) for this pest.
Here we describe a new species of the genus Aeolothrips that has recently been discovered in mango crops in the Isthmus region of Oaxaca in southern Mexico. This predatory thrips may be important in controlling many species of phytophagous thrips that attack this crop.
Aeolothrips romanruizi sp. nova.
HOLOTYPE ♀. MEXICO, Oaxaca, San Pedro Tapanatepec, N 16°27′18.5″ W 94°13′23.5″, 46 m asl. Paratypes: 14 ♀ ♀, same data the holotype. Holotype and 4 paratypes deposited in the collection IBUNAM of the Universidad Autonoma de Mexico, 5 paratypes deposited in the collection of the Universidad de Costa Rica and 5 paratypes deposited in the Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional (CIIDIR), IPN-Unidad Oaxaca.
Color. Body mostly dark brown. Legs with dark brown femora and tibiae. Wings pale translucent with two brown bands longer than wide (Fig. 1A). Major setae dark brown.
Antennal segments I-IX dark brown, except segment III (and extreme base of segment IV) which is completely yellow (Fig. 1B). Antennal segments III-V longer than wide and cylindrical, with parallel sides and with several rows of microtrichia. Segments VI-IX forming a style, sensoria on III-IV well developed, linear and longer than half the length of the segment (Fig. 3A)
Head. As long as wide, with many randomlyplaced, long, thin setae in the postocular region. Ocellar setae short. Back of the head with widelyspaced striations. Well-developed eyes with multiple ommatidia, the eye is longer in the ventral face than on the dorsal face (Figs. 1C and 3B). Mouth cone long and strong, maxillary palpi well developed, with 3 segments (Fig. 1D).
Prothorax. Wider than long, with many discal setae, anteromarginals setae reduced, posteromarginal setae stronger and longer than the other setae on the pronotum. Posteromarginal setae I more developed than posteromarginal II and III. Discal region without ornamentation with several discal setae shorter than posteromaginals I and II (Figs. 2A and 3B). Ferna entire.
Sizes in µm of morphological traits of the holotype: total body length= 1850, total length of the antenna = 372.5; I = 30, II = 55, III = 95, IV = 92.5, V = 57.5, VI-VIII = 10, IX = 12.5, pedicel length of antennal segments III and IV, 7.5 and 2.5 respectively; am = 15, amm = 15, PMI = 25, PMII = 20, PMIII = 15, = 430 ovipositor.
The species name is dedicated to the memory of Roman Ruiz Sánchez in recognition of his dedication and hard work as an evangelical pastor.
Specimens of Aeolothrips romanruizi sp. nova collected in Oaxaca possess the following characters (those in italics are considered diagnostic of Aeolothrips by Mound & Marullo (1996)): antenna with 9 segments, sensory in segments III-IV linear VI-IX short and condensed to form a unit, compound eyes prolonged ventrally, maxillary palpi with 3 segments, head and pronotum without setae, posteromedial pair of setae on the metanotum, forewing with 1 or 2 bands of dark color with clear apex, abdominal sternites IV-VI with setae and without discal setae marginal or ancillary, sternite VII with 2 pairs of accessory setae submarginal.
The previously described species of Aeolothrips have ornamentation of the mesonotum and metanotum different from that of A. romanruizi sp. nova. In most species the ornamentation of the mesonotum is striated and with widely spaced lines, and usually the metanotum is reticulated. The only described species showing ornamentation similar to that of A. romanruizi sp. nova is microstriatus (Hood 1935). Aeolothrips romanruizi sp. nova is known only from the holotype, from a male collected in Panama, and from a specimen collected in Brazil by an anonymous reviewer that has not been described because of insufficient material. Hood (1935) stated that the species, A. microstriatus, differs from others by having a bicolored body, especially in the abdomen, antennae with light brown segments, a single band on the anterior part of the wing I, and unique ornamentation of the pterothorax. The new species A. romanruizi sp. nova has an entirely dark brown body (Fig. 1A), the segments of the antenna are dark brown with the exception of III, which is bright yellow (Fig. 1B). The wing has 2 dark brown bands and the many striations on the mesonotum and metanotum of the pterothorax with many closely spaced together (Fig. 2D), similar to microstriatus.
COMPARISON BETWEEN THE PRINCIPAL CHARACTERS RELATING TO SEXUAL DIMORPHISMS IN THE MOST ABUNDANT AEOLOTHRIPS SPECIES IN AMERICA, NAMELY, THE COLOR PATTERNS OF THE BODY, ANTENNAE AND WINGS, AS WELL AS CLASPERS, SETAE AND TUBERCLES IN MALES.
Color pattern in Aeolothrips
The color pattern in many groups of thrips is critical in separating species, as evidenced by keys developed by multiple authors (zur Strassen 1997). Recently it has been shown that in some groups like in Frankliniella some color patterns may be of phylogenetic importance and may be useful in determining groups of species (Retana-Salazar 2010). The key of Mound & Marullo (1996) is still the most complete for the determination the New World Aeolothrips species. In this key 60% of the items involve the use the color pattern in the separation of species, and this is valid for both males and females.
A review of the main Aeolothrips species found in America (Table 1) indicates that the greatest variation in color pattern between males and females is manifested in the coloration of the antennomeres, especially in the coloration of antennomere III. In some species antennomere III is dark in males and clear in females. Furthermore, and consistent with the key by Mound & Marullo (1996), the color pattern of the body and wings remains constant between female and male Aeolothrips. Consequently these well studied characters are widely used in the segregation of species within Aeolothrips.
Among the most notable color variations of the wings that are widely used in the separation of species are; (1) the type of the banding of wing I, (2) the width of the bands, and (3) the presence or absence of a longitudinal band on the posterior edge of wing 1. In the descriptions the wing has arbitrarily been divided into the sections anterior and posterior, dividing the wing into the fraction close to the body and the other fraction distant from the body which includes the apical end of the wing.
The correct terms for the two parts are proximal, the part nearest to the body, and distal the part including the apical end. In this text we use the terms proximal and distal.
In the new species, A. romanruizi sp. nova, described in this paper the color pattern consists of a dark brown body and a pale translucent wing with two discontinuous dark brown bands. In contrast the body of A. microstriatus is bicolored; being brownish red and the wings have a dark band, according to the original description of Hood (1935). In view of the stability of the coloration of the 2 genders of Aeolothrips in which wing color pattern is of importance in the separation of species, we consider that the metanotum striations and the distinct wing color pattern of A. romanruizi sp. nova indicate that it belongs to the Aeolothrips microstriatus group.
On the other hand, the widely different distribution of A. microstriatus and the new species, A. romanruizi sp. nova found in Oaxaca, Mexico, makes it difficult to assume that it is the female of microstriatus. The wing color pattern of A. romanruizi sp. nova seems to approach the new species more to other Mexican species, but differing in the structure of the metanotum.
KEY TO CENTRAL AMERICAN AND MEXICAN SPECIES OF AEOLOTHRIPS
1a) Body bicolored 2
1b) Body entirely dark in color 3
2a) Forewing with one dark band in the second fourth, abdominal segments III-VIII pale microstriatus Hood 1935
2b) Forewing with two dark bands, abdominal segments II-III pale bicolour Hinds 1902
3a) Forewing with posterior margin with a dark area well defined from base to apex, eventually a dark transverse band may be arise from this longitudinal dark margin 4
3b) Forewing with two transverse dark bands, posterior margin pale between bands 5
4a) Head length shorter than 190 µm major Bailey 1951
4b) Head length longer than 220 µm mexicanus Priesner 1924
5a) Antennal segment III largely dark brown, yellowish brown in basal half duvali Moulton 1927
5b) Antennal segment III with at least clear yellow in basal three quarters 6
6a) Antennal segment III clear yellow in basal three quarters, metanotal sculpture weakly reticulated surcalifornianus Johansen 1989
6b) Antennal segment III totally clear yellow, metanotal sculpture striated with closely spaced lines transverse in anterior third but concentric in posterior area romanruizi sp. nova.
To the Consejo Nacional de Ciencia y Tecnología (CONACyT) for the financial support to carry out this research, derived of the project “Evaluatión de nuevas variedades con alto potencial productivo y diagnostico y control de piagas de importancia ecónomica del mango en Guerrero, Veracruz, Chiapas y Oaxaca”. Alcides Sánchez-Monge for his comments on the original draft, Dr. Odalisca Breedy-Shadid for the revision of the English narrative, Alexander Rodríguez-Arrieta for his cooperation, and the project “Estudio morfológico y genético de los estados inmaduros de thrips (Thysanoptera:Insecta) de relevancia económica en Hispanoamérica”, 810-B1–224. Also an anonymous reviewer provided information regarding the existence of this material in South America.