Fine‐scale genetic structure reflects sex‐specific dispersal strategies in a population of sociable weavers (Philetairus socius)

Dispersal is a critical driver of gene flow, with important consequences for population genetic structure, social interactions and other biological processes. Limited dispersal may result in kin‐structured populations in which kin selection may operate, but it may also increase the risk of kin competition and inbreeding. Here, we use a combination of long‐term field data and molecular genetics to examine dispersal patterns and their consequences for the population genetics of a highly social bird, the sociable weaver (Philetairus socius), which exhibits cooperation at various levels of sociality from nuclear family groups to its unique communal nests. Using 20 years of data, involving capture of 6508 birds and 3151 recaptures at 48 colonies, we found that both sexes exhibit philopatry and that any dispersal occurs over relatively short distances. Dispersal is female‐biased, with females dispersing earlier, further, and to less closely related destination colonies than males. Genotyping data from 30 colonies showed that this pattern of dispersal is reflected by fine‐scale genetic structure for both sexes, revealed by isolation by distance in terms of genetic relatedness and significant genetic variance among colonies. Both relationships were stronger among males than females. Crucially, significant relatedness extended beyond the level of the colony for both sexes. Such fine‐scale population genetic structure may have played an important role in the evolution of cooperative behaviour in this species, but it may also result in a significant inbreeding risk, against which female‐biased dispersal alone is unlikely to be an effective strategy.     

The nutritional contribution of males affects the feeding behavior and spatial distribution of females in a bruchid beetle,<Emphasis Type="Italic"> Bruchidius dorsalis</Emphasis>

The relationship between the quality/quantity of male investment and the feeding behavior of females was investigated in a bruchid weevil, Bruchidius dorsalis (Fahraeus), whose males donate nutrition via seminal fluid to females. Experiments on the effect of feeding regimes of both sexes on the mating frequency of females showed that females mated at a higher frequency if given low-quality food or poor male investment. On the other hand, the experiment that examined the effect of male investment quality on female feeding behavior showed that females receiving the high-quality investment exhibited feeding behavior less often. These results suggest that male investment and feeding behavior play the same role for B. dorsalis females. These experiments also showed that there are sex-related asymmetries in mating and feeding behaviors: females mated more often but males fed more often. Moreover, a field census suggested that only males visited non-host flowers to feed on the pollen and nectar during the non-flowering period of the host plants; females always stayed on the host plants irrespective of the flowering phenology. These results suggest that in B. dorsalis courtship role reversal and sex-specific feeding modes are fairly fixed and obligatory, and that male investment, derived from sexual selection, could affect the feeding behavior and spatial distribution of both sexes, which may have far-reaching impact in various ecological contexts.     

Costs and benefits of giant sperm and sperm storage organs in Drosophila melanogaster

In Drosophila, long sperm are favoured in sperm competition based on the length of the female's primary sperm storage organ, the seminal receptacle (SR). This sperm–SR interaction, together with a genetic correlation between the traits, suggests that the coevolution of exaggerated sperm and SR lengths may be driven by Fisherian runaway selection. Here, we explore the costs and benefits of long sperm and SR genotypes, both in the sex that carries them and in the sex that does not. We measured male and female fitness in inbred lines of Drosophila melanogaster derived from four populations previously selected for long sperm, short sperm, long SRs or short SRs. We specifically asked: What are the costs and benefits of long sperm in males and long SRs in females? Furthermore, do genotypes that generate long sperm in males or long SRs in females impose a fitness cost on the opposite sex? Answers to these questions will address whether long sperm are an honest indicator of male fitness, male post‐copulatory success is associated with male precopulatory success, female choice benefits females or is costly, and intragenomic conflict could influence evolution of these traits. We found that both sexes have increased longevity in long sperm and long SR genotypes. Males, but not females, from long SR lines had higher fecundity. Our results suggest that sperm–SR coevolution is facilitated by both increased viability and indirect benefits of long sperm and SRs in both sexes.     

The management of metabolic energy storage during the life cycle of mayflies: a comparative field investigation of the collector-gatherer <Emphasis Type="Italic">Ephemera danica</Emphasis> and the scraper <Emphasis Type="Italic">Rhithrogena semicolorata</Emphasis>

The concentration and seasonal dynamics of the major energy storage components, triglycerides and glycogen, were measured in two species of mayfly (Rhithrogena semicolorata and Ephemera danica) with contrasting life cycle strategies living in a small mountain stream. E. danica is a burrowing, semivoltine collector-gatherer; R. semicolorata is univoltine and scrapes periphyton from stones. This is the first publication which focuses on the role of metabolic energy sources during the larval life span of two mayfly species until the larvae emerge. Although triglycerides are the major energy reserve in both species (>84% of total energy storage) throughout the whole larval development their seasonal dynamic differed considerably. In R. semicolorata the triglyceride concentration declined during the last weeks prior to emergence in both sexes. The same pattern was found in female larvae of E. danica, but not in male E. danica. It is suggested that females use triglycerides in the last larval stages for egg maturation, which is completed in the last larval instar. In male E. danica the triglyceride concentrations remained high until emergence, presumably due to their high energy demands as adults for their swarming flights. Glycogen concentrations did not show such a difference between species and sexes. Its significance as a storage substrate for energy is rather low; however, concentrations decreased in both species and sexes prior to emergence.     

Effects of size‐ and sex‐selective harvesting: An integral projection model approach

Harvesting is often size‐selective, and in species with sexual size dimorphism, it may also be sex‐selective. A powerful approach to investigate potential consequences of size‐ and/or sex‐selective harvesting is to simulate it in a demographic population model. We developed a population‐based integral projection model for a size‐ and sex‐structured species, the commonly exploited pike (Esox lucius). The model allows reproductive success to be proportional to body size and potentially limited by both sexes. We ran all harvest simulations with both lower size limits and slot limits, and to quantify the effects of selective harvesting, we calculated sex ratios and the long‐term population growth rate (λ). In addition, we quantified to what degree purely size‐selective harvesting was sex‐selective, and determined when λ shifted from being female to male limited under size‐ and sex‐selective harvesting. We found that purely size‐selective harvest can be sex‐selective, and that it depends on the harvest limits and the size distributions of the sexes. For the size‐ and sex‐selective harvest simulations, λ increased with harvest intensity up to a threshold as females limited reproduction. Beyond this threshold, males became the limiting sex, and λ decreased as more males were harvested. The peak in λ, and the corresponding sex ratio in harvest, varied with both the selectivity and the intensity of the harvest simulation. Our model represents a useful extension of size‐structured population models as it includes both sexes, relaxes the assumption of female dominance, and accounts for size‐dependent fecundity. The consequences of selective harvesting presented here are especially relevant for size‐ and sex‐structured exploited species, such as commercial fisheries. Thus, our model provides a useful contribution toward the development of more sustainable harvesting regimes.     

Growing old with the immune system: a study of immunosenescence in the zebra finch (<Emphasis Type="Italic">Taeniopygia guttata)</Emphasis>

Immunosenescence has not received much attention in birds and the few existing studies indicate that the occurrence of immunosenescence and/or its extent may differ between species. In addition, not much information is available on the immunosenescence patterns of different immune parameters assessed simultaneously in both sexes within a single species. The present study reports the results on immunosenescence in innate immunity and both cellular and humoral acquired immunity of both sexes in a captive population of zebra finch (Taeniopygia guttata) using three age groups (approximately 0.2, 2.5 and 5.1 years). Both male and female finches showed an inverse U-shaped pattern in cellular immune function with age, quantified by a PHA response. Males showed stronger responses than females at all ages. In contrast, an increase with age in humoral immunity, quantified through total plasma immunoglobulin Y levels, was found in both sexes. However, our measurements of innate immunity measured through the bacteria-killing ability against Escherichia coli gave inconclusive results. Still, we conclude that both cellular and humoral acquired immunity are susceptible to immunosenescence, and that the sexes differ in cellular immunity.     

Sexual differences in response to simulated herbivory in the gynodioecious herb <Emphasis Type="Italic">Geranium sylvaticum</Emphasis>

Several factors have been proposed to explain female maintenance in gynodioecious populations. In this study, we propose and test a novel hypothesis: greater tolerance to herbivory through more beneficial interactions with plant fungal mutualists might also help to explain female maintenance. Herbivory limits the amount of carbon and nutrients available for the plants and has been shown to affect mycorrhizal colonization. We hypothesized that simulated herbivory would decrease reproductive output, mycorrhizal colonization intensity, and the phosphorus content relatively more in hermaphrodites, so females would achieve higher advantage over hermaphrodites when under herbivory pressure. We tested it in the field using the gynodioecious plant Geranium sylvaticum. We found that simulated herbivory had a negative effect on the reproductive output in both sexes and that there was a similar reduction in fruit set, seed set, and total seed number in both sexes. Defoliation did not affect any fungal parameter measured, but decreased phosphorus content relatively more in females. The plants had a sex-specific relationship with mycorrhizae, but this was not related to herbivory. Thus, we conclude that females do not gain any specific advantage under defoliation from its symbionts at short-term even though it seems that the plants have sex-specific relationship with their mycorrhizal symbionts.     

Physiological costs of cold exposure on the parasitoid <Emphasis Type="Italic">Aphidius ervi</Emphasis>, without selection pressure and under constant or fluctuating temperatures

The aim of this study is to evaluate the physiological costs and the consequences on fitness of cold exposure on the parasitoid Aphidius ervi (Hymenoptera: Aphidiinae) under non-lethal conditions. We exposed 1-day-old mummies to different treatments: control at 20°C, 7°C constant, 7°C fluctuating (7°C for 22 h and 20°C for 2 h). Two performances of fitness were particularly affected after two weeks at 7°C constant: female longevity and the sex ratio of the progeny was male biased. In contrast, egg load at emergence, lifetime fecundity, frequency of asymmetric individuals in both sexes, and mating success were not significantly affected under all treatments. The effects of these treatments on trends such as utilisation of fat reserves and fertility of males and females are discussed.     

Behavioral Differences of the Insect Morimus funereus (Coleoptera,Cerambycidae) Exposed to an Extremely Low Frequency Magnetic Field

Changes in the behavior of Morimus funereus individuals were investigated as early manifestations of the contact of a living system with a changed environment primarily established via the nervous system. These experiments were aimed at revealing possible behavioral differences of a laboratory population of cerambycid beetle M. funereus in an “open field” before and after exposure to an extremely low frequency magnetic field (ELF‐MF, 50 Hz, 2 mT). The experimental groups were divided into several activity categories and exposed to ELF‐MF. The results showed that the activity increased in the groups with medium and low motor activity, but decreased in highly active individuals. High individual variability was found in the experimental groups, as well as differences in motor activities between the sexes, both before and after exposure to ELF‐MF. According to preliminary results, we assume the changes of activity in both sexes after exposure to ELF‐MF. The results showed a tendency toward locomotor activity decrease, the affect being more pronounced in females. As opposed to this type of activity, stereotypic activity of males was increased after the exposure, whereas females maintained the expected tendency of decrease. However, we did not obtain statistically significant differences because of a high individual variability and a low total number of individuals in the experiment (N = 28). Only a detailed analysis of the locomotor activity at 1‐min intervals showed some statistically significant differences in behavior between the sexes.     

Sexually dimorphic expression and estradiol mediated up‐regulation of a sex‐linked ribosomal gene,RPS6, in the zebra finch brain

Sex‐linked genes are considered to be a major contributor to neural sex differences in zebra finches. While several candidates have been identified, additional ones are continuously being discovered. Here we report on a novel Z‐linked ribosomal gene (rpS6) that is enhanced in the male brain as compared to the female's throughout life. In both sexes, expression of rpS6 is highest at P3 and P8 (just before the onset of morphologically detectable sex differences), decreases around P15, and then remains decreased through adulthood. Analysis of rpS6 mRNA revealed widespread distribution throughout the brain. However, within song regions HVC and RA, mRNA containing cells were greater in males as compared to females. Hormones are also involved in the development of neural dimorphisms, so we additionally investigated whether rpS6 might interact with estradiol (E₂). An up‐regulation of rpS6 gene was observed in both sexes following treatment with E₂ and the effect was approximately twice as large in males as compared with females. These data suggest that rpS6 may be involved in sexual differentiation of the zebra finch brain, and that the effect is facilitated by E₂. © 2013 Wiley Periodicals, Inc. Develop Neurobiol 73: 599–608, 2013     

Sex‐ratio in natural and experimental populations of Drosophila subobscura from North America

The sex‐ratio (SR), defined as the proportion of males, has been studied in three North American colonizing populations of Drosophila subobscura (Eureka, Davis and Gilroy). The proportion of sexes under laboratory conditions was studied using the one‐generation serial transfer technique in one‐ and two‐species populations, to infer whether biased SR affects the outcome when competing with Drosophila pseudoobscura, another member of the same group now in sympatry with D. subobscura in North America. The wild samples of D. subobscura yielded a significantly higher number of males than females during those months where the species is more abundant. However, there was no significant deviation in the 1 : 1 proportion of sexes in the descendants of D. subobscura at any of the experimental conditions. On the contrary, D. pseudoobscura produced a higher proportion of females which could be responsible for the exclusion of D. subobscura in laboratory competition experiments with overlapping generations. Thus, if sexes are equal at birth and survival is similar, the preponderance of males of D. subobscura in our wild collections could indicate greater activity and probably greater chance of dispersal of males versus females especially under favourable conditions.     

Which proximate factor determines sexual size dimorphism in tiger snakes?

Diverse interactions between factors that influence body size complicate the identification of the primary determinants of sexual size dimorphism. Using data from a long‐term field study (1997–2009), we examined the contributions of the main proximate factors potentially influencing sexual size dimorphism from birth to adulthood in tiger snakes (Notechis scutatus). Data on body size, body mass and body condition of neonates, juveniles and adults were obtained by mark–recapture. Frequent recaptures allowed us to monitor reproductive status, diet and food intake, and to estimate survival and growth rates in age and sex classes. Additional data from females held briefly in captivity enabled us to assess reproductive output and the body mass lost at parturition (proxies for reproductive effort). From birth to maturity, individuals of both sexes experienced similar growth and mortality rates. We found no difference in diet, feeding and survival rates between the sexes, nor between juveniles and adults. On maturity, despite comparable diet and food intake by both sexes, the high energy requirements of vitellogenesis and gestation were responsible for a depletion of body reserves and probably resulted in a marked decrease in growth rates. Males were largely exempt from such costs of reproduction, and so could grow faster than females and attain larger body sizes. The absence of niche divergence between the sexes (uniformity of habitat, lack of predators) suggests that the impact of differential energetic investment for reproduction on growth rate is probably the main proximate factor influencing sexual size dimorphism in this species. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 668–680.     

Tail Length and Mutual Mate Choice in Bearded Tits (Panurus biarmicus)

Direct sexual selection via mutual mate choice can result in both sexes showing conspicuous traits. We experimentally tested whether this hypothesis can explain tail length in the bearded tit (Panurus biarmicus). In this species, both sexes have a long, graduated tail. Males have, however, a longer tail than females, suggesting perhaps that females are choosier than males in selecting mates. We used two choice set‐ups for each sex: shortened vs. control tail individuals and elongated vs. control tail individuals. We found that direct sexual selection seems to operate differently in the two sexes. In both set‐ups, females spent more time with the male with the longest tail, and they also showed sexual display behaviour only towards these males. Males spent more time with control than with short‐tailed females, but they did not discriminate between control and long‐tailed females. Moreover, males displayed preference towards both short‐ and long‐tailed females. Thus, females preferred long‐tailed males, whereas males did not always prefer long‐tailed females. Our study suggests that mutual mate choice has played a role in the evolution of long tails in bearded tits. It also suggests that the sexual dimorphism in tail length has evolved because mate choice exerts a stronger sexual selection pressure on males than on females.     

Flight potential of <Emphasis Type="Italic">Microplitis mediator</Emphasis>, a parasitoid of various lepidopteran pests

The efficacy of using natural enemies to control pests under field conditions largely depends on their mobility and, more specifically, on their capacity to quickly locate pest infestation. For many natural enemies, for example parasitoids, mobility is directly related to flight aptitude, which is determined by the capacity and inclination of a species to engage in flight. In this study, we determined the various factors that affected flight performance of Microplitis mediator (Haliday) (Hymenoptera: Braconidae), using a computer-monitored flight mill. No differences were found in flight performance (i.e., flight distance, duration, speed) between both sexes of M. mediator, and flight capacity increased up to an age of 5–7 days followed by a gradual decline afterwards. For one-day-old female parasitoids, mean (±SE) flight distance and duration were 6.23 ± 0.88 km and 85.15 ± 14.44 min, respectively, with a maximum flight distance of 18.0 km. For male parasitoids, mean flight distance and duration were 5.27 ± 0.51 km and 85.74 ± 7.63 min, respectively. Mating status did not affect flight performance of males, while flight distance of four-day-old ovipositing M. mediator females was much lower than that of un-mated females of the same age. Un-mated adults flew most actively at 22–24°C and inclination to fly gradually declined with decreasing temperature. Temperatures above 26°C considerably reduced flight activity of M. mediator. Wasps engaged in normal flight under a broad range of relative humidity (RH) conditions, with an optimum RH range identified as 75–90%. Our research shows that M. mediator is a highly active parasitoid, because both sexes show great inclination to fly under a range of environmental conditions and flight capacity at different ages. Our results can help explain parasitoid performance in the field and provide baseline information to help guide augmentative releases. Handling editor: Dirk Babendreier.     

The M16 Mouse: An Outbred Animal Model of Early Onset Polygenic Obesity and Diabesity

Objective: To characterize the phenotypic consequences of long‐term selective breeding for rapid weight gain, with an emphasis on obesity and obesity‐induced diabetes (diabesity). Research Methods and Procedures: M16 is the result of long‐term selection for 3‐ to 6‐week weight gain from an ICR base population. Experiment 1 characterized males from both lines for body weights (3, 6, and 8 weeks), feed (4 to 8 weeks) and H₂O (6 to 8 weeks) consumption, and heat loss, body composition, and levels of several plasma proteins at 8 weeks of age. Experiment 2 characterized differences between lines for both sexes at three ages (6, 8, and 16 weeks) and fed two diets (high and normal fat). Body weight, composition, blood glucose, and plasma insulin and leptin levels were evaluated after an 8‐hour fast. Results: At all ages measured, M16 mice were heavier, fatter, hyperphagic, hyperinsulinemic, and hyperleptinemic relative to ICR. M16 males and females were hyperglycemic relative to ICR, with 56% and 22% higher fasted blood glucose levels at 8 weeks of age. Discussion: M16 mice represent an outbred animal model to facilitate gene discovery and pathway regulation controlling early onset polygenic obesity and type 2 diabetic phenotypes. Phenotypes prevalent in the M16 model, with obesity and diabesity exhibited at a young age, closely mirror current trends in human populations.     

Longevity costs of same‐sex interactions: first evidence from a parasitic wasp

Costs of sexual interactions play a key role in life‐history evolution. Although the costs of reproduction have been investigated in both sexes of many insects, the costs of same‐sex interactions have been examined in few species. In parasitic wasps, very little has been reported about the longevity costs of heterosexual interactions, and nothing is known about longevity costs of same‐sex interactions. In this study, the effects of heterosexual and homosexual activities on longevity were evaluated in Psyttalia concolor (Hymenoptera: Braconidae), a synovigenic koinobiont larval‐pupal endoparasitoid of tephritid flies. When compared with individually housed virgin wasps, male longevity was strongly reduced both in males kept with females, and in males kept with other males. When females were kept with males, their longevity was reduced compared with the virgin females and females kept with other females. Overall, the costs of male–female interactions were considerable in both sexes of P. concolor, while same‐sex activities were found to be costly only among males, suggesting that they may have implications for the evolution of the P. concolor mating system.     

Reproductive Success and Sexual Selection in Wild Eastern Tiger Salamanders (<Emphasis Type="Italic">Ambystoma t. tigrinum</Emphasis>)

Variation in reproductive success is most pronounced in species with strongly biased operational sex ratios, prominent sexual dimorphisms, and where mate competition and choice are likely. We studied sexual selection in eastern tiger salamanders (Ambystoma t. tigrinum) and examined the role of body size on reproductive success. We genotyped 155 adults and 1,341 larvae from 90 egg masses at six microsatellite loci. Parentage analyses revealed both sexes engaged in multiple matings, but was more common among females (64%) than males (27%). However, the standardized variance in mating and reproductive success was higher in males. Bateman gradients were significant and nearly identical in both sexes, suggesting that sexual selection was roughly equal between sexes. Body size was not correlated with mating or reproductive success in either sex. The apparent lack of sexual selection on body size may be a result of sperm storage, sperm competition, alternative mating tactics, and/or random induction of spermatophores.     

Length–length relationship, length–weight relationship, gonadosomatic index, condition factor, size at maturity and fecundity of Parastromateus niger (Carangidae) in Kuwaiti waters

Analyses of morphometric parameters of the black pomfret, Parastromateus niger, in the Kuwaiti waters of the Arabian Gulf during a 44‐month study revealed the following length‐length relationships: TL (cm) = 0.63 + 1.15SL (females), TL (cm) = 0.94 + 1.14SL (males) and TL (cm) = 0.75 + 1.15SL (both sexes including juveniles). The 95% CI of the exponent in length‐weight relationship varied from 2.788 to 2.796 in females, 2.726 to 2.732 in males, 2.779 to 2.784 for both sexes and 2.590 to 2.613 in juveniles, all indicating an allometric relationship. Simultaneous analysis of Fulton’s condition factor (K) and GSI indicate that spawning in black pomfret peaks in May and June even though the fish remain in good condition throughout the spawning season. The Fulton’s condition factor was statistically discriminatory in determining the well‐being of P. niger. Variation in average maximum condition was significant between sexes and also higher in 2004 as compared to 2005. The mean size at first sexual maturity (SL_50%) was 17.5 cm for males and 29 cm for females. Fecundity ranged from 71 305 to 3 895 449 eggs and correlated positively with: (a) ovary‐free body weight (P < 0.05), standard length (P < 0.05) and ovary weight (P < 0.05), and negatively with egg size (P > 0.05). Fecundity‐total length relationship was best described by the logarithmic equation of the form F = 0.898 + 3.15 × TL^3.15. The use of results of such morphometric studies in the management of the P. niger species in the Arabian Gulf is suggested due to its growing commercial importance.     

Sexual dimorphism and sexual selection in a montane scincid lizard (Eulamprus leuraensis)

Sex‐based divergences in body sizes and/or shapes within a species imply that selective forces act differently on morphological features in males versus females. That prediction can be tested with data on the relationship between morphology and reproductive output in females, and between morphology and realized paternity (based on genetic assignment tests) in males. In a sample of 81 field‐collected adult Blue Mountains water skinks (Eulamprus leuraensis), males and females averaged similar overall body sizes (snout–vent lengths (SVLs)). Reproductive success (based on 105 progeny produced by the females) increased with SVL at similar rates in both sexes (as expected from the lack of sexual size dimorphism). Multiple paternity was common. Males had larger heads than females of the same body size, and (as predicted) reproductive success increased with relative head size in males but not in females. Males also had relatively longer limbs and shorter trunks than females, but we did not detect significant sex differences in selection on those traits. Reproductive success in both sexes was increased by relatively longer hind limbs. Our data clarify mating systems in this endangered species, and suggest that mating systems are diverse within the genus Eulamprus.     

Confirmation of the existence of alloparasitoids in nature – host relationships of an Australian Coccophagus species that parasitizes mealy bugs

Heteronomous hyperparasitoids are parasitic wasps with sex‐related host relationships that are unique to a group of genera in the chalcidoid family Aphelinidae. Females are primary parasitoids of various sedentary bugs (mainly, scale insects, mealy bugs, and whiteflies). Males, in contrast, are hyperparasitic, and they frequently develop at the expense of female conspecifics. Alloparasitoids constitute a special category of heteronomous hyperparasitoids, for their males never develop through female conspecifics. The existence of alloparasitic host relationships and the utility of the category ‘alloparasitoid’ have both been questioned. Here, we present results that confirm the existence of the alloparasitic way of life among heteronomous aphelinids. We investigated an undescribed species of Coccophagus (Hymenoptera: Aphelinidae), an Australian parasitoid that attacks the introduced lantana mealy bug, Phenacoccus parvus Morrison (Homoptera: Pseudococcidae), in Queensland. A year‐long field survey regularly returned large numbers of female Coccophagus spec. near gurneyi individuals from P. parvus (total n = 4212), but only few males (n = 11). Males emerged from samples only when the encyrtid parasitoid Anagyrus diversicornis (Howard) (Hymenoptera: Encyrtidae) was present in samples in relatively high numbers. Laboratory oviposition tests confirmed that A. diversicornis is a male host and showed that males do not develop at the expense of conspecific females. Other studies show that males are attracted in numbers to virgin females held in cages above mealy bug‐infested Lantana montevidensis (Spreng.) Briq. (Verbenaceae) in the field, demonstrating that they are common in the population as a whole. This confirms that the males need hosts other than conspecific females and that their usual hosts are present outside of the lantana/P. parvus system. The implications of these results for developing a realistic classification of heteronomous host relationships are discussed.