Orlando Cómbita-Heredia

Primary and secondary sexual characters of Mesostigmata are often used in species descriptions and phylogenetic analyses. The use of these characters has been focused almost exclusively on external structures such as the male chelicera and genital plates, while internal structures have only been utilized for lightly sclerotized species.

Synchrotron X-ray microtomography (SR-mCT) is a noninvasive technique that has the potential to reduce our knowledge gap on the internal morphology of mites. This technique allows for the creation of three-dimensional representations of organisms and is particularly relevant to taxonomy, evolution, systematics, ecology, and biodiversity.

Chelicerae of most Parasitiform mites have retained the same general set of plesiomorphic structures and functions. For mesostigmatid mites this represents grabbing, cutting, piercing and, in the males of some groups, transferring sperm (Di Palma 2009).

Studies of female genital structures have generally lagged behind comparable studies of male genitalia, in part because of an assumption of a lower level of variability, but also because internal genitalia are much more difficult to study. Using multiple microscopy techniques, including video stereomicroscopy, fluorescence microscopy, low-temperature scanning electron microscopy (LT-SEM), and confocal laser scanning microscopy (CLSM) we examined whether the complex sperm transfer structures in males of Megalolaelaps colossus (Acari: Mesostigmata) are matched by similarly complex internal structures in the female. While both LT-SEM and CLSM are well suited for obtaining high-quality surface images, CLSM also proved to be a valuable technique for observing internal anatomical structures. The long and coiled sperm transfer organ on the chelicera of the males (spermatodactyl) largely matches an equally complex, but internal, spiral structure in the females in shape, size, and direction. This result strongly suggests some form of genital coevolution. A hypothesis of sexual conflict appears to provide the best fit for all available data (morphology and life history).

Biological invasions impact both agricultural and natural systems. The damage can be quantified in terms of both economic loss and reduction of biodiversity. Although the literature is quite rich about the impact of invasive species on plant and animal communities, their impact on environmental microbiomes is underexplored. Here, we re-analyze publicly available data using a common framework to create a global synthesis of the effects of biological invasions on environmental microbial communities. Our findings suggest that non-native species are responsible for the loss of microbial diversity and shifts in the structure of microbial populations. Therefore, the impact of biological invasions on native ecosystems might be more pervasive than previously thought, influencing both macro- and micro-biomes. We also identified gaps in the literature which encourage research on a wider variety of environments and invaders, and the influence of invaders across seasons and geographical ranges.

Seven species of mites were found associated with the dung beetle Oxysternum conspicillatum in Colombia. Macrocheles neotransversus sp. nov. based on adults and the male of Macrocheles magna are described. Both species belong to the mitis species-group (Holocelaeno). Macrocheles boxi, M. phanaei, M. roquensis and Glyptholaspis confusa are reported for the first time in Colombia. Additionally, a case of hyperphoresy of deutonymphs of Histiostoma sp. on Megalolaelaps colossus is documented. http://www.zoobank.org/urn:lsid:zoobank.org:pub:304E0CA6-EED2-4819-B9F0-24A85D283E86

A new species of blattisociid mites Lasioseius orangrimbae n. sp., that belongs to the floridensis-group, is described based on females and males from litter and soil samples of secondary rainforest in Sumatra, Indonesia.

Aspects of life history and host interactions of Megalolaelaps colossus were studied in a laboratory environment. These mites appear to require a host for survival, but hosts do not survive very long in a laboratory setting, leading to a modified rearing protocol relying on regular host replacement. Specific data on phenology and incidence are reported. Direct observations on feeding, mating, transmission, and interaction with other mites could not be obtained, but indirect observations allow some hypotheses in each of these areas.

Post-embryonic development of Megalolaelaps colossus sp. nov., is described and illustrated. This unusually large species of mite is closely associated with the dung beetle Oxysternon conspicillatum (Weber) (Coleoptera: Scarabaeidae) in Colombia. All instars of the mite occur on the beetle, except for the larva. This is the first description of all instars for a species in this genus.