Biology subjects

Gorb, S. N.

Publications and source records attributed to Gorb, S. N..

3 recordsLinked to original sources

bioRxiv2021

Multi-modal locomotor costs explain sexual size but not shape dimorphism in a leaf-mimicking insect

In most arthropods, adult females are larger than males, and male competition is a race to quickly locate and mate with scattered females (scramble competition polygyny). In this context, smaller males may be favored due to more efficient locomotion leading to higher mobility during mate searching while larger males may benefit from increased speed and higher survivorship. Understanding how body size affects different aspects of the locomotor performance of males is therefore essential to shed light on the evolution of this widespread mating system. Using a combination of empirical measures of flight performance and substrate adhesion, and modelling of body aerodynamics, we show that large body size impairs both flight and landing (attachment) performance in male leaf insects (Phyllium philippinicum), a species where relatively small and skinny males fly through the canopy in search of large sedentary females. Smaller males were more agile in the air, ascended more rapidly during flight, and had a lower risk of detaching from the substrates on which they walk and land. Our models revealed variation in body shape affected body lift and drag, but tradeoffs with weight meant that effects were negligible, suggesting that flight costs do not explain the evolution of strong sexual dimorphism in body shape in this species. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=177 SRC="FIGDIR/small/451325v1_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@193d0adorg.highwire.dtl.DTLVardef@1693bccorg.highwire.dtl.DTLVardef@1d50b53org.highwire.dtl.DTLVardef@1da8572_HPS_FORMAT_FIGEXP M_FIG C_FIG

ecology↗

bioRxiv2020

The temperature-dependent predatory strike of Odonata larvae

The larvae of Odonata are limnic predators capable of catching their prey using a highly modified mouthpart - the labium. Driven by a unique dual catapult mechanism, the apparatus can reach peak accelerations of up to 114.5m/s2. Yet little is known about the kinematics of the predatory strike in an ecological context. Here we show how different ambient temperatures affect the predatory strike and the avoidance reaction of prey items of Odonata larvae. We found that the extension velocity of the labial mask decreases significantly with the ambient temperature both in dragonflies and damselflies. However, temperature has lesser impact on the predatory strike itself than on directly muscle driven movements in both the predator and prey items. This contradicts the previous assumption that catapult mechanisms in insects are unaffected by temperature. Our results indicate that the prehensile labial mask is driven by a series-elastic catapult; a mechanism similar to the temperature dependent jump of frogs, where muscle and spring action are tightly linked. Our study provides novel insights into the predatory strike of Odonata larvae and offers a new ecological perspective on catapult mechanisms in arthropods in general.

zoology↗

bioRxiv2020

A ballistic pollen dispersal strategy hidden in stylar oscillation

Asteraceae, the most successful flowering plant family, is adapted to the vast range of ecological niches. Their adaptability is partially based on their strong ability of reproduction. The initial, yet challenging, step for plant reproduction is to transport pollen to flower-visiting pollinators. Using quantitative experiments and numerical simulations, here we show that the common floral feature of Asteraceae, a pollen-bearing style, serves as a ballistic lever for catapulting pollen grains to pollinators. This is likely to be a pollination strategy to propel pollen to blind spots of pollinators bodies, which are beyond the physical reach of the styles. Our results suggest that the specific morphology and length of the floret, as well as the pollen adhesion, avoid pollen waste by catapulting pollen within a certain range equal to the size of a flowerhead. The insights into the functional floral oscillation may shed light on the superficially unremarkable, but ubiquitous functional floral design of Asteraceae.

plant biology↗