Looking for future biological control agents: the comparative function of the deutosternal groove in mesostigmatid mites

Abstract

The physics of fluid laminar flow through an idealised deutosternum assembly is used for the first time to review predatory feeding designs over 72 different-sized example species from 16 mesostigmatid families in order to inform the finding of new biological control agents. Gnathosomal data are digitised from published sources. Relevant gnathosomal macro- and micro-features are compared and contrasted in detail which may subtly impact the control of channel- or ‘pipe’-based transport of prey liquids around various gnathosomal locations. Relative deutosternal groove width on the mesostigmatid subcapitulum is important but appears unrelated to the closing velocity ratio of the moveable digit. Big mites are adapted for handling large and watery prey. The repeated regular distance between deutosternal transverse ridges (‘Querleisten’) supports the idea of them enabling a regular fluctuating bulging or pulsing droplet-based fluid wave ‘sticking’ and ‘slipping’ along the groove. Phytoseiids are an outlier functional group with a low deutosternal pipe flow per body size designed for slot-like microchannel transport in low volume fluid threads arising from daintily nibbling nearby prey klinorhynchidly. Deutosternal groove denticles are orientated topographically in order to synergise flow and possible mixing of coxal gland-derived droplets and circumcapitular reservoir fluids across the venter of the gnathosomal base back via the hypostome to the prey being masticated by the chelicerae. As well as working with the tritosternum to mechanically clean the deutosternum, denticles may suppress fluid drag. Shallow grooves may support edge-crawling viscous flow. Lateral features may facilitate handling unusual amounts of fluid arising from opportunistic feeding on atypical prey. Various conjectures for confirmatory follow-up are highlighted. Suggestions as to how to triage non-uropodoid species as candidate plant pest control agents are included.

Do astigmatid teeth matter: a tribological review of cheliceral chelae in co-occuring mites from UK beehives

“…To a degree, free-living, non-parasitic mites must be opportunistic feeders whose chelicerae can serve multiple functions. For instance, phytoseiids despite being specialist predators (Bowman 2023b) also eat pollen and yeasts, mesostigmatids from the family Parasitidae eat fly larvae yet also decaying flesh, even Tyrophagus spp. consume nematodes (not just fungi).…”

“…On the face of isometry is seemingly rejected (at least between C. lactis and the other two species). However, it is now clear from this review, that acarine dentition patterns are an adapted module within an adapted chelal module (Bowman 2021c(Bowman , 2023a within an adapted cheliceral/gnathosomal module (Bowman 2021b(Bowman , 2023b. Moreover, although these can be embedded into a rational scheme of life style, each element is not necessarily strongly correlated, so the appropriate divisor to definitively scale R t is not clear.…”

“…Discretisation bias is not allowed for in for the concave nature of the relationships need strong cleaning, so its gullets do not need to be large ( abs(R v ) < 1 μm). Microroughness of a surface affects its 'wettability' (Bowman 2023b). How sticky is astigmatid food material in the field?…”