Allogalumna (Acrogalumna) longipluma (^{Berlese, 1904}) (Oribata elimata l.).

Galumna decipiens Mihelčič, 1956

Galumna filata Oudemans, 1914

Galumna latipluma Mihelčič, 1952

Galumna longiporus Mihelčič, 1952

Oribata setiformis Hall, 1911

World distribution: wide distribution: Holarctic, Ethiopic, Oriental (India: Kerala and southeastern China), and New Zealand (Subias, 2004, updated 2021).

Material examined: 48 specimens (28 ♀ and 20 ♂) - MEXICO (new country record), Michoacán: El Rosario, Municipality of San Juan Nuevo, 19° 23' 27.8" N, 102° 10' 30.8" W, 2160 masl. 2 specimens (1 ♀ and 1 ♂) - Tanaxuri, Municipality of Uruapan, Mi Ranchito 1 farm, 19° 23' 47.2" N, 102° 05' 58.1"W, 1683 masl.

Habitat: litter and forest floor of Pinus devoniana, Quercus rugosa and avocado (Persea americana Var. Hass).

Biological cycle

Oviposition and fertility. The female has a telescopic ovipositor (Fig. 11), which allows her to deposit eggs in narrow hollows to protect them (^{Estrada-Venegas, 2008}; ²⁰¹²). Under laboratory conditions, females oviposited one or several eggs in openings in the environment, remains of organic matter, exuviae from other developmental stages, or among the pteromorphs of dead adults (Figs. 1-4). Females may oviposit four to five eggs, which is consistent with previous reports by ^{Jacot (1934)}. Several females can use the same area for oviposition; up to 14 eggs were counted in an exuvia or four to six eggs in the same brood hole; in many cases, the use of the same site for oviposition can complicate the exit of the larvae after hatching, since they can become trapped and after two or three days they die of inanition. Oviposition began 50 days after adult emergence (Table 1) and lasted about 20 days.

Figures 1-11 Biology of Allogalumna (Acrogalumna) longipluma: 1) Newly oviposited eggs. 2-3) Oviposition strategies. 4) Egg close to hatching. 5) Larva. 6) Protonymph. 7) Deutonymph. 8) Tritonymph. 9) Adult. 10) Quiescence and molt. 11) Female with ovipositor extended. Scale = 100 µm. 

Egg. The incubation period of the egg was 10.1 ± 1.8 days (n = 14). This value is close to the incubation period of 11.8 and 10.8 days reported by ^{Sengbusch (1954)} and ^{Sengbusch (1958)}; respectively, in these works the author reports that the brood was maintained at 25° C and 82% relative humidity.

Larva. At the beginning of emergence, the egg opens at the anterior pole towards the middle of the egg and allows the larva to emerge forward. Upon emergence, the larva remains attached to the chorion for 12 to 24 hours; during this time, several individuals were observed feeding on the remains of the chorion (Fig. 5). The larval period had a duration of 12 ± 2.6 days (7.7 ± 1.9 days active and 4.3 ± 0.7 quiescence), the result differs by +1 day with ^{Sengbusch (1954)} and -1 day with ^{Sengbusch (1958)}.

Nymphs. The development period for protonymph was 11.2 ± 1.8 days (7.1 ± 1.3 days active and 4.1 ± 0.5 quiescence), for deutonymph was 12.6 ± 2.9 days (8.3 ± 2.2.2 days active and 4.3 ± 0.7 quiescence) and for tritonymph was 16.4 ± 3.8 days (9.4 ± 2.6 days active and 7 ± 1.3 quiescence). The results for protonymph and deutonymph resemble those obtained by ^{Sengbusch (1954)} and differ with ^{Sengbusch (1958)} by -1 day, the tritonymph time difference is +1 day with the first work and -1 with the second. As ontogenetic development proceeds, the nymphs feed more voraciously, and their locomotion becomes more agile.

Adult. The life span of adults was 155 ± 57 days, the variance is considerably high, principally because some individuals were infected by fungi that were developed in the rearing medium, inhibited their feeding until they were killed; these individuals lived between 104 to 107 days, however, two individuals lived 226 and 247 days respectively. None of the authors cited above report the lifetime of adults. During this stage, feeding is more voracious and constant than in the nymphal stages, while locomotion becomes less agile. ^{Estrada-Venegas et al. (1999)} mention that this is because adults are bigger than nymphs, which makes locomotion more difficult.

Reproduction. During the observation period, the deposition of spermatophores on the substrate was not evidenced, however, populations increased exponentially, which allows us to assume that this species reproduces by parthenogenesis. ^{Pauly (1956)} and ^{Sengbusch (1958)} report sperm transfer by spermatophores and also parthenogenesis. According to ^{Norton (1994)}, about 10% of oribatid species can reproduce asexually in a facultative way, as a response to habitat alteration and allows them to double their reproductive rate.

Quiescence and molt. Individuals move away from food two to three days before entering quiescence, during this time they look for cracks, hollows, and exuviae of deutonymphs and tritonymphs to go through this process, these spaces can be occupied by one of the dozens of individuals, which, if they converge at the beginning of quiescence, can return to the same site in the four processes of quiescence and molting. The growth of the organisms causes the idiosome to expand, between the circumgastric suture and the dorsosejugal suture, this condition is an obvious sign that the individual is close to the quiescence period. The day before molting, the body becomes darker in color and the old cuticle becomes iridescent as it separates due to the formation of the new cuticle; the old cuticle breaks from the posterior region of the circumgastric suture, is directed anteriorly around the gastral line, and allows the individual to emerge posteriorly (hysterodehiscent) (^{Norton & Behan-Pellelier, 2009}) (Fig. 10). Quiescence takes 4 to 4.3 days in the larva, protonymph, and deutonymph, while in the tritonymph it can take as long as nine to ten days (Table 1).

Feeding habits. This species showed a strong preference for dog croquettes (Biscuit, Pedigree®) and yeast flakes, occasionally they were observed consuming decomposed plant tissue, dead galumnids covered with fungus remains of springtails, and dead diplurans. However, they rejected pine pollen, algae, and lichens. Under laboratory conditions, adults showed greater voracity than nymphs and larvae. ^{Sengbusch (1954)} fed his galumnids with the bark of trunks covered with green alga Protococcus sp., also tried to feed them with apple peel, potato, germinated wheat seeds, rice, oats, yeast, sugar water, and malt; however, he obtained little or no successful results.

Morphological description

Egg (Figs. 1-4). Length 66.4 (62.7-68.7), width 46.1 (44.5-47.7). Eggs are oval, milky white iridescent, darkening as embryonic and pre-larvae development progresses to a slightly yellowish white coloration. The shape of the egg also changes as the days go by the anterior pole tends to narrow to a typical ovoid shape. In advanced stages of development (one or two days before emergence) the three pairs of legs directed towards the posterior pole of the egg and the sclerotized gnathosoma can be observed (Fig. 4).

Larva (Fig. 5). Body ovoid, notogaster rounded, anterior part of prodorso rounded, narrower than posterior. Body length 313.95 (313-314.9), width 223.9 (219.7-229.1); body sparsely sclerotized, color light beige on notogaster, while prodorso varies between dark beige and light brown. Prodorsal setae black; rostral (ro) 44.2 (44-45.2), lamellar (le) 45.9 (40.1-50.2) and interlamellar (in) 33.2 (32.3-34.6) setiform and barbed. Lamellar and rostral setae projected anteriorly, the latter shorter, thicker, and with its anterior ends slightly curved and convergent. Sensillum black, elongate 73.6 (64.1-79.0), fusiform, with wide capitulum 4.6 (4.3-5.0) and barbulate (Table 2); bothridium cup-shaped, the ends of it not converging appearing to form a coil, the basal part of the sensillum arranged wavy on the bothridium; exobotridial setae (ex) 22.8 (22.1-23.2) straight, barbulate and located posterolateral to the bothridium. Legs more sclerotized than rest of body, total length (trochanter-tarsus) leg I:158.6 ± 5.8 µm, leg II: 159.3 ± 6.6 µm and leg III: 163.6 ± 15.6 µm; tarsus on leg I slightly larger than on legs II and III (Table 3). Tarsal formula of legs (solenidia in parentheses) I: 0-2-2-2(1)-3(1)-3(1)-16(1); II: 0-2-2-2(1)-2(1)-13(1); III: 0-2-1(1)-2(1)-13 (Table 4). Tarsus I-III monodactyl. Notogaster with 11 pairs of minute setae, three pairs of porose areas (Aa, A1, and A2) rounded, faint grayish almost imperceptible and arranged laterally on notogaster; setae c3 larger than setae c2. Epimeral region with chaetotaxial formula 3-2-1. Anal aperture 85.4 (64.5-86.3); setae h2 positioned contiguous to the anal plate and h1 slightly posterolateral to the former; opisthonotal glands nearly aligned with the anterior part of the anal plate and arranged on the flanks of the anogenital region.

Protonymph (Figs. 6, 12). body length 379.3 (371.5-391.3), width 288.5 (285.2-291.6). Length of setae ro, 53.8 (52.5-53.9), le 64.6 (64.4-64.7), in 40 (38.5-42.4), ex 30.5 (27.5-32.5), ss 78.3 (75.9-82.3); sensillar capitulum dilatation shows a slight reduction 3.7 (3.5-4. 0) compared to the larva; the exobotridial setae are larger than the larva, the same situation occurs with the lamellar and rostral setae, they show the similar thickness and are arranged completely parallel on the prodorsum. The setae c3 almost doubles its length compared to the previous stage 40.2 (40.0-40.4), while c2 shows only a slight increase of 14 (13.9-14.0) (Table 2). Legs (Figs. 13-16) much more sclerotized than the larva, total length (trochanter-tarsus) leg I: 182.4 ± 5.9 µm, leg II: 158.4 ± 8.2 µm, leg III: 190.3 ± 3.9 µm and leg IV: 210.4 ± 4.7 µm; leg I and III larger than the larva, leg II shows no difference in size. The segments of leg IV are larger than in the other legs, except the femur which is longer in leg I (Table 3). Chaetotaxy formula of legs (solenidia in parentheses) I: 0-4-2(1)-3(2)-16(2); II: 0-4-2(1)-3(1)-13(2); III: 0-2-1(1)-2(1)-13; IV: 0-2-2-2-1(1) -12 (Table 4). The solenidion ω2 appears on tarsus I and the setae (p), ft'', (u), (pv) on tarsus IV. Notogaster with 15 pairs of minute setae how in the larva and four porose areas (Aa, A1, A2, A3), all circular, the first three of dark grayish color quite evident, the coloration of A3 fainter and less evident; this pattern is also repeated in the deutonymph and tritonymph. Epimeral region with chaetotaxy formula 3-1-2-1. Anal aperture 103.4 (94.8-107.4), genital plate primordium 33.6 (32.4-34.4), with a pair of genital setae and acetabulum. Opisthonotal glands are larger and conspicuous.

Figures 12-16 Allogalumna (Acrogalumna) longipluma, protonymph: 12) Entire body, ventral view. 13) Leg I. 14) Leg II. 15) Leg III. 16) Leg IV. Scale = 100 µm. 

Deutonymph (Figs. 7, 17). Body length 471.9 (453.1-482.3), width 375.7 (359.4-391.7). Prodorsum triangular, length of setae ro, le, in, ex and sensillum increases in size relative to protonymph; setae in and le are more barbulate than in protonymph. The sensillum shows considerable changes in its length 99.2 (97.1-102.9), but not in its capitulum width, and remains with the same dimensions until tritonymph. The notogastral setae are smaller than in the protonymph, becoming almost imperceptible; porose areas increase in size. The setae c3 shows a developmental rate similar to that of the previous nymphal stage (9-11 µm), in contrast, c2 shows a higher elongation rate of 22.9 (22.0-24.2) (Table 2). The length of legs I and III show an increase of 20 and 13 µm respectively concerning the protonymph, in legs II and IV the growth is greater (62 and 41 µm) (Figs. 18-21). The length of legs I and III show an increase of 20 and 13 µm respectively concerning the protonymph, in legs II and IV the growth is greater (62 and 41 µm) (Figs. 18-21). Chaetotaxy increases, the most evident is found in leg IV, where setae d, ev' (femur), d, l' (genua), v', φ (tibia) and setae (tc), (a), s (tarsus) are added, chaetotaxy formula of legs (solenidia in parentheses): I: 0-4-2-2(1)-3(2)-16(2); II: 0-4-2(1)-3(1)-13(2); III: 0-2-1(1)-2(1)-13; IV: 0-2-2-2-1(1)-12 (Table 4). In epimere IV, seta 4b is added, epimeral region formula 3-1-2-2-2, maintained until tritonymph and adult. Anal aperture 120.0 (113.3-132.0), two pairs of anal setae, three adanal, lyrifissure iad located anterior to ad3 setae; genital plate primordium 46.9 (45.2-47.9) with three pairs of genital setae.

Figures 17-21 Allogalumna (Acrogalumna) longipluma, deutonymph: 17) Complete body, ventral view. 18) Leg I. 19) Leg II. 20) Leg III. 21) Leg IV. Scale = 100 µm. 

Tritonymph (Fig. 8). Body growth is considerably greater than in the previous stage of development, length 658.5 (647.9-675.0), width 531.2 (511.8-542.0); further sclerosing of the body causes it to take on a brown, slightly reddish coloration; prodorsal setae increase in length relative to the deutonymph (Table 2). Similarly, the development and size of the humeral organ (oh) is greater. Porose areas Aa presents an anteromedial orientation in notogaster; the growth rate of legs (Table 3) is greater than in deutonymph; setae v' are added on trochanters I-IV and genua I-II, seta v'' on tibia I, seta l' on tibiae III-IV and seta (it) on tarsus I-III; chaetotaxy formula of legs (solenidia in parentheses): I: 1-4-3(1)-4(2)-18(2); II: 1-4-3(1)-3(1)-15(2); III: 1-2-1(1)-3(1)-15; IV: 1-2-2-2(1)-12 (Table 4). Anal opening 162.4 (158.6-170.1); genital plate primordium 73 (69.5-74.4), five pairs of genital setae, and three acetabulum also present in the adult stage.

Adult (Figs. 9, 11): Body length 623.3 (590.3-634.4), width 597.5 (568.1-628.5); body strongly sclerotized, light brown post molt and progressively darkening in later days to dark brown coloration. Prodorsal setae rather long, seta in 123.3 (119.4-131.2) larger, setae le 111.1 (108.2-114.4) larger than setae ro 70.5 (64.3-83.0); the latter with a curvature in the anterior middle portion that converges at the ends. Sejugal porose areas Ad elongate widened medially and located posterior to setae in. Sensillum elongate, setiform, and barbulate from middle onwards 206.5 (191.1-217.3); length up to double compared to tritonymph, width almost reduced by half 2.6 (2.3-3.0). L-line absent. Notogaster with five pairs of porose areas; Aa'' large, subtriangular, arranged next to pteromorph joint, Aa' two to three times smaller, circular or oval, located between lm and la setae, A1 circular, between lp and h3, A2 oval, elongate, located posterolateral to the anterior, A3 more elongate than last and accommodated slightly transverse to notogaster, between h1, p1, and p2. Pteromorphs auriculate, with multiple descending branching lines; a stria crosses transversely the median region, between alveolus c2 and lirifisura ia, terminating as a sclerotized canal near the pteromorph joint. Setae c2 and c3 are absent. Median pore absents in female, male with 44 (40-54) pores between porose areas A3. Legs considerably larger than tritonymph, total length trochanter tarsus (I: 460.3 ± 8.4 µm, II: 359 ± 12.4 µm, III: 360.4 ± 9.1 µm and 465.4 ± 4.5 µm). Setae v', l'' are added on tarsus I, v''', l'' on tibia II and IV respectively; chaetotaxy formula of legs (solenidia in parentheses): I: 1-4-3(1)-4(2)-20(2); II: 1-4-3(1)-4(1)-15(2); III: 1-2-1(1)-3(1)-15; IV: 1-2-2-3(1)-12. Anal aperture reduced compared to tritonymph 149 (134.7-157.6), anal and adanal setae minute, lirifisura iad paraanal; genital aperture 95.6 (90.0-104.7), six pairs of genital setae, g1-4 arranged medially on plate, g5-6 on upper edge. Opisthonotal glands are positioned on notogaster next to porose areas A1.