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| Coecobrya microphthalma Manee & Jantarit, in Manee, Deharveng, D’Haese, Nilsai, Shimano et Jantarit, 2025. |
Abstract
A new species of Collembola in the genus Coecobrya, C. microphthalma sp. nov., is described from a cave environment in Saraburi province, central Thailand. The new species is the second described species of the boneti-group found in the country. It is most similar to C. chompon Nilsai, Lima & Jantarit, 2022, which is also described from a Thai cave. However, the new species is morphologically different from C. chompon in having orange dot pigmentation on its body and a combination of other morphological characteristics such as the number of sublobal hairs on the maxillary outer lobe and the number of medio-sublateral mac on Th. II, Abd. I, Abd. III and Abd. IV and the anterior face of the ventral tube. The morphological comparison of all known boneti species and a key to the world species of Coecobrya of the boneti-group are given. Coecobrya microphthalma sp. nov. was successfully cultured in the laboratory. The thermal tolerance of the new species was studied and tested with seven different temperature experiments (27 °C as a control, 30, 32, 33, 34, 35 and 36 °C). The results showed that C. microphthalma sp. nov. cannot survive at a temperature higher than 32 °C after exposure to the experimental heat for 7 and 14 consecutive days. At 27, 30 and 32 °C, C. microphthalma sp. nov. remained alive and produced eggs, but the duration of egg production and number of egg-laying days significantly declined when the temperature increased (p < 0.001). An interesting aspect of their reproduction concerns temperature. At 32 °C (5 °C above the control temperature), the F1 generation survived, was active and was able to molt to the adult stage. However, specimens were unable to produce the next generation of offspring. For postembryonic development, C. microphthalma sp. nov. required six molts to reach the adult stage. The development rate (from egg to adult) varied and differed significantly between the tested temperatures (p < 0.001). An increase in temperature from the control temperature significantly accelerated the developmental rate from egg to juvenile instars to adult with a statistical significance (p < 0.01). This study is the first attempt that provide information on the impact of increasing temperature on the population dynamics, reproductive capacity and life history of a subterranean tropical Collembola.
Keywords: breeding experiment; cave species; global warming; life history traits; thermal tolerance; taxonomy
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| Coecobrya microphthalma sp. nov. (A) habitus under microscope; (B) habitus under SEM; (C) head and black eyepatch under slide; (D) head and eye (arrow) under SEM; (E) enlargement of eye under SEM. Scale bar: (A,B)= 500 μm, (D) = 100 μm, (E) = 10 μm ((A,C): microscope images; (B,D,E): SEM images). |
Taxonomy
Class Collembola Lubbock, 1870
Order Entomobryomorpha Börner, 1913
Family Entomobryidae Tömösváry, 1882
Subfamily Entomobryinae Schäffer, 1896
Genus Coecobrya Yosii, 1956
Coecobrya microphthalma sp. nov. Manee and Jantarit, 2025
Remarks. Coecobrya microphthalma sp. nov. belongs to the boneti-group characterized by the presence of eyes. The new species has 1+1 small eyes like six other species of the same group (C. boneti (Denis, 1948), C. sanmingensis Xu and Zhang, 2015, C. indonesiensis (Chen and Deharveng, 1997), C. tukmeas Zhang, Deharveng and Chen, 2009, C. oculata Zhang, Bedos and Deharveng, 2016 and C. chompon). Among Thai cave species, Coecobrya microphthalma sp. nov. is most similar to C. chompon in having relatively long antennae, labial chaetae as mrel1l2, presence of long smooth straight chaetae on antennae, 3 medio-medial mac on Th. II, 3 central mac on Abd. II, 1 central mac and …
Etymology. Coecobrya microphthalma sp. nov. is derived from the Latin meaning “having small eyes”.
(This article belongs to the Section Other Arthropods and General Topics)
Simple Summary: A new species of Collembola, Coecobrya microphthalma sp. nov., is described from a cave in Saraburi province, central Thailand. This species is the second boneti-group member found in the country. It closely resembles C. chompon Nilsai, Lima & Jantarit, 2022 but differs in having orange body dots and distinct morphological traits, such as the number of sublobal hairs and mac on various body segments. A comparison of all boneti-group species globally and a key to their identification are provided. Coecobrya microphthalma sp. nov. was cultured in the laboratory, and its thermal tolerance was tested at seven different temperatures (27 °C as control, 30, 32, 33, 34, 35, and 36 °C). The results showed that it cannot survive above 32 °C after 7 and 14 days of exposure. At 27, 30, and 32 °C, the species remained alive and produced eggs, though egg-laying duration and number of days decreased with higher temperatures. At 32 °C, the F1 generation survived and molted to adulthood, but no further offspring were produced. Development from egg to adult required six molts, with development rates increasing with higher temperatures. This study is the first attempt to examine how temperature affects the population dynamics, reproductive capacity, and life history of a subterranean tropical Collembola.
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