A new construction of a drop volume apparatus has proved to be successful in determining the interfacial tension for a variety of pure liquids as well as for solutions having surface tensions, which come to equilibrium quickly. Temperature dependence of the surface tension can easily be recorded even at elevated temperatures, which has been shown for water.

We investigated inbreeding depression and genetic load in a small (Ne ∼ 100) population of the Glanville fritillary butterfly (Melitaea cinxia), which has been completely isolated on a small island [Pikku Tytärsaari (PT)] in the Baltic Sea for at least 75 y. As a reference, we studied conspecific populations from the well-studied metapopulation in the Åland Islands (ÅL), 400 km away. A large popul

On small isolated islands, natural selection is expected to reduce the dispersal capacity of organisms, as short distances do not require a high rate of dispersal, which might lead to accidental emigration from the population. In addition, individuals foregoing the high cost of maintaining flight capacity may instead allocate resources to other functions. However, in butterflies and many other ins

A new procedure for the application of the drop volume technique to measurements of the rate of adsorption of proteins at interfaces has been developed. The mode of adsorption of the proteins lysozyme, β-lactoglobulin and bovine serum albumin (BSA) at the air-water interface has been measured with the drop volume method and has been compared to measurements with the Wilhelmy plate technique. Due t

Habitat loss and fragmentation threaten the long-term viability of innumerablespecies of plants and animals. At the same time, habitat fragmentation mayimpose strong natural selection and lead to evolution of life histories with possibleconsequences for demographic dynamics. The Baltic populations of the Glanvillefritillary butterfly (Melitaea cinxia) inhabit regions with highly fragmented habitat

Dr. Anne‐Marie Hermansson is heartily thanked for her kind interest in this work, and Dr. P. Walstra is thanked for his valuable comments. The authors are also much indebted to Ing. Ernst Braun for valuable advice during the construction of the emulsifying apparatus and for making the construction drawings. The practical construction work of the valve homogenizer and the ultra‐turrax by Jan Walter

1. The Glanville fritillary butterfly (Melitaea cinxia L.) has a small population (Ne ∼ 100) on the small island of Pikku Tytärsaari (PT) in the Gulf of Finland. The population has remained completely isolated for ∼100 generations, which has resulted in greatly reduced genetic variation and high genetic load (low fitness). In particular, females lay small egg clutches with a low egg‐hatching rate

The adsorption behaviour of three food proteins, a soy protein isolate, a sodium casein‐ate and a whey protein concentrate, at the air‐water interface has been studied by the drop volume method. The kinetics of surface tension decay were evaluated in terms of different rate‐determining steps at different ionic strengths and concentrations. This analysis indicates the following characteristics conc

Protein stabilised emulsions have been prepared in a valve homogeniser incorporated into a recirculating emulsification system, where the power input and number of passes have been varied. The food proteins studied were a soy‐bean protein isolate, a whey protein concentrate (WPC) and a sodium caseinate. The emulsions obtained were characterized in terms of particle size distribution and amount of

The maternally transmitted bacterium Wolbachia pipientis is well known for spreading and persisting in insect populations through manipulation of the fitness of its host. Here, we identify three new Wolbachia pipientis strains, wHho, wHho2 and wHho3, infecting Hyposoter horticola, a specialist wasp parasitoid of the Glanville fritillary butterfly. The wHho strain (ST435) infects about 50% of the i

The success of maternally transmitted endosymbiotic bacteria, such as Wolbachia, is directly linked to their host reproduction but in direct conflict with other parasites that kill the host before it reaches reproductive maturity. Therefore, symbionts that have evolved strategies to increase their host’s ability to evade lethal parasites may have high penetrance, while detrimental symbionts would

The emulsifying properties of proteins have been a subject concern for those dealing with functional properties of proteins. The studies so far have been restricted to two main approaches: emulsifying capacity and emulsion stability measurements. The former measures the maximum oil addition until inversion or phase separation of the emulsion occurs, whereas the latter measures the ability of the e

BackgroundAdaptation to local habitat conditions may lead to the natural divergence of populations in life-history traits such as body size, time of reproduction, mate signaling or dispersal capacity. Given enough time and strong enough selection pressures, populations may experience local genetic differentiation. The genetic basis of many life-history traits, and their evolution according to diff

In butterflies, male reproductive success is highly related to the quality and the size of the spermatophore transferred to the female. The spermatophore is a capsule produced by the male during copulation, which in many species contains sperm in addition to a nuptial gift, and which is digested by the female after copulation. The nuptial gift may contribute to egg production and offspring quality

Bicyclusbutterflies are key species for studies ofwing pattern development, phenotypic plasticity, speciationand the genetics of Lepidoptera. One of the key endosymbi-onts in butterflies, the alpha-ProteobacteriumWolbachiapipientis, is affecting many of these biological processes;however, Bicyclusbutterflies have not been investigated sys-tematically as hosts toWolbachia.Inthisstudy,wescreenforWo

The Lepidoptera is one of the most widespread and recognisable insect orders. Due to their remarkable diversity, economic and ecological importance, moths and butterflies have been studied extensively over the last 200 years. More recently, the relationship between Lepidoptera and their heritable microbial endosymbionts has received increasing attention. Heritable endosymbionts reside within the h