Sex allocation theory has proved to be one the most successful theories in evolutionary ecology. However, its role in more applied aspects of ecology has been limited. Here we show how sex allocation theory helps uncover an otherwise hidden cost of neonicotinoid exposure in the parasitoid wasp Nasonia vitripennis. Female N. vitripennis allocate the sex of their offspring in line with Local Mate Competition (LMC) theory. Neonicotinoids are an economically important class of insecticides, but their deployment remains controversial, with evidence linking them to the decline of beneficial species. We demonstrate for the first time to our knowledge, that neonicotinoids disrupt the crucial reproductive behaviour of facultative sex allocation at sub-lethal, field-relevant doses in N. vitripennis. The quantitative predictions we can make from LMC theory show that females exposed to neonicotinoids are less able to allocate sex optimally and that this failure imposes a significant fitness cost. Our work highlights that understanding the ecological consequences of neonicotinoid deployment requires not just measures of mortality or even fecundity reduction among non-target species, but also measures that capture broader fitness costs, in this case offspring sex allocation. Our work also highlights new avenues for exploring how females obtain information when allocating sex under LMC.

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Abstract. 1. Neonicotinoid insecticides are potent neurotoxins of significant economic importance. However, it is clear that their use can adversely impact beneficial insects in the environment, even at low, sub-lethal doses.2. It has recently been shown that the neonicotinoid imidacloprid disrupts adaptive sex allocation in the parasitoid wasp Nasonia vitripennis (Walker) by limiting their ability to respond to the presence of other females on oviposition patches. In the present study, that work was extended to explore whether sex allocation when superparasitising -laying eggs on a host that has already been parasitised -is also disrupted by imidacloprid.3. Under superparasitism, sex allocation theory predicts that females should vary their offspring sex ratio in relation to their relative clutch size. It was found that sex allocation under superparasitism in Nasonia is disrupted in a dose-dependent manner, with exposed females producing more daughters.4. Importantly, imidacloprid does not appear to influence the ability of females to estimate the number of eggs already present on a host, suggesting a disassociation between the sex ratio and clutch size cues.5. The present work highlights the fitness costs to beneficial insects of exposure to neonicotinoids, but also provides clues as to how female Nasonia use information when allocating sex.

Micelles of hydrophilic−hydrophobic block copolymers, such as poly(ethylene glycol)-block-poly(caprolactone) (PEG-b-PCL), are useful for delivery of hydrophobic drugs. Such micelles can be formed by liquid solvent displacement or dialysis. A more recent approach is to use supercritical fluids as solvents, but the selection criteria for solvents are not well understood. The compressible solvents studied in this work can induce pressure-tunable micellization of PEG-b-PCL. Their capacity and selectivity, and hence their ability to form micelles, depends on their density, polarity, and hydrogen bonding potential. By mixing two solvent components, such as dimethyl ether (good solvent) and trifluoromethane (selective antisolvent), one can control not only the micellization temperature and pressure, but also the bulk separation pressure (cloud pressure), crystallization temperature, and melting temperature. This can be utilized to develop efficient ways to prepare micellar precursors for drug-loaded nanoparticles.

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