Predicting protein condensate formation using machine learning

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Sperm length evolution in the fungus-growing ants

Eusocial insects offer special opportunities for the comparativestudy of sperm traits because sperm competition is absent (inspecies with obligatory monandry) or constrained (in lineageswhere queens mate multiply but never remate later in life).We measured sperm length in 19 species of fungus-growing ants,representing 9 of the 12 recognized genera, and mapped theseonto the ant phylogeny. We show that average sperm length acrossspecies is highly variable and decreases with mature colonysize in basal genera with singly mated queens, suggesting thatsperm production or storage constraints affect the evolutionof sperm length. Sperm length does not decrease further in multiplymating leaf-cutting ants, despite substantial further increasesin colony size. In a combined analysis, sexual dimorphism explained63.1% of the variance in sperm length between species. As colonysize was not a significant predictor in this analysis, we concludethat sperm production trade-offs in males have been the majorselective force affecting sperm length across the fungus-growingants, rather than storage constraints in females. The relationshipbetween sperm length and sexual dimorphism remained robust inphylogenetically independent contrasts. Some of the remainingvariation was explained by the relative size of the sperm-storageorgan, but only in the multiply mating leaf-cutting ants, suggestingthat sperm-storage constraints become important for the evolutionof sperm length in this derived group. Mate number affectedsperm length to a minor extent, and only in interaction withother predictor variables, suggesting that sperm competitionhas not been a major selective force for sperm length evolutionin these ants.     

A dye-binding induced conformational transition of poly-(methacrylic acid) by Auramine O in aqueous solutions. I. Experimental results

Binding of auramine O to poly-(methacrylic acid) (PMA) has been established over a large range of C⁰_p/C⁰_d values using spectroscopic methods (UV absorption and visible fluorescence emission spectra), equilibrium and sedimentation dialysis, potentiometric and viscosimetric titrations. All the results show qualitative agreement with those obtained previously with the system crystal violet-PMA although the binding seems to be less strong for auramine O than for crystal violet. From dialysis experiments binding isotherms were obtained at three different degrees of neutralization α'; at α' = 0.10 the results could be fitted to a Langmuir isotherm but at α' equal to 0.40 and 0.65 deviations with respect to such an isotherm occur. The results of potentiometric and viscosimetric titrations confirm that the conformational transition which the dye-free PMA exhibits upon ionization is affected by the dye binding. The region in which the conformational transion occurs is broadened and is less sharply defined in the presence of auramine O.     

The Conservation of Saproxylic Insects in Tropical Forests: A Research Agenda

Invariably, insects are overlooked when tropical forest management issues are discussed, because there are so many species, they are taxonomically intractable and so poorly known. Often people take the view that if you look after the vegetation and vertebrates, the insects will look after themselves. This may be true for some functional groups, but for saproxylic insects, this seems unlikely. Their study deserves high priority, since they are dependent on the very resource – wood – whose removal from the ecosystem is the usual object of forest management. Given the current international effort to develop 'criteria and indicators' to monitor sustainable forest management for biodiversity values, there is a window of opportunity for sound ecological research on saproxylic insects to influence the formulation of forest policy such that their needs can be taken into account. There is already a large body of knowledge on temperate and boreal region saproxylic insects, and on the effects that logging has on them, but knowledge of the tropical forest situation lags far behind. This paper proposes a research agenda to enable the needs of saproxylic insects to be taken into account in natural forest management in the tropics. Basic questions, such as whether logging has so far had an impact on tropical saproxylic insects, and whether there are workable sampling techniques to investigate this, still remain to be addressed and deserve high priority. The links between the responses of saproxylic insects and more 'charismatic' study species need to be investigated. We also need to know whether there is a correlation between the intensity of logging and the response of saproxylic insects, and, critically, whether we would be justified in measuring some surrogate aspects of forest structure (as potential habitat for saproxylic insects) rather than the saproxylic insects themselves, and modelling this to determine likely impacts of different management regimes. We consider such an ambitious research agenda as justified given the scale of impact that forest use and management is likely to have on tropical forest insects in the future.     

Optimal transportation theory for species interaction networks

1. Observed biotic interactions between species, such as in pollination, predation, and competition, are determined by combinations of population densities, matching in functional traits and phenology among the organisms, and stochastic events (neutral effects).
2. We propose optimal transportation theory as a unified view for modeling species interaction networks with different intensities of interactions. We pose the coupling of two distributions as a constrained optimization problem, maximizing both the system''s average utility and its global entropy, that is, randomness. Our model follows naturally from applying the MaxEnt principle to this problem setting.
3. This approach allows for simulating changes in species relative densities as well as to disentangle the impact of trait matching and neutral forces.
4. We provide a framework for estimating the pairwise species utilities from data. Experimentally, we show how to use this framework to perform trait matching and predict the coupling in pollination and host–parasite networks.

The coupling between species in a species interaction network can be modeled using optimal transportation. As an application of the MaxEnt principle, it jointly maximizes interaction utility and entropy. This allows for anticipating how the interaction coupling can change when species abundances change.     

Zur sozialen Funktion des Gesanges der Amsel Turdus merula L.

Im Brutrevier einer Stadt-Amsel konnte eine situationsgemäße, zweckgerichtete Anwendung des Amselgesanges beobachtet werden. Vom Amsel-♂ wurden Anfangsteile von Gesangsstrophen oder vollständige Strophen als Aufforderung an das ♀ benutzt, das Nest zur Futtersuche zu verlassen.