Number Of Adult Males Research Articles

How many pheasants (Phasianus colchicus L.) can be removed? A study on small protected areas in Italy

In Italy the maintenance and the increase of wild pheasant populations is mainly obtained in small-Protected Areas (PA) suitable for wildlife reproduction. In these areas a part of the resident population is regularly captured and transferred to the hunting zones in the winter time. The aim of the study is to determine the right number of pheasant to be removed from this protected area without causing damage and thus maintaining a balance in the resident population. Since 2000, flush counts census were conducted in 30 PAs in the Florence province during the summer time (post-reproduction period), using dogs experienced at rooting out the pheasants. We made estimates for each PA in the number of adult males, adult females and sexually undifferentiated young pheasants. We calculated post-reproduction density and the ratios of young/adults and males/females. These parameters were used to construct a model to predict the pheasants catches in the next winter. The study showed that the minimum census surface covered must be more than 9% of the total area studied. Smaller cover- age gave biased estimations of pheasant numbers to be caught. The best generic model, to be used for surfaces between 297 and 1385 ha, located in Mediterranean habitats, was the following: total number of pheasants to be captured and relocated = -10.3 + 0.15*total number of female pheasants estimated in the protected area + 0.14* total number of young pheasants estimated in the protected area + 0.04*total surface of the protected area (R 2 = 0.48).

Litter size and infant survivorship in wild groups of cotton‐top tamarins (Saguinus oedipus) in Colombia

Cotton-top tamains (Saguinus oedipus) are a critically endangered primate found only in Colombia. Efforts to conserve this species are centered on developing effective management plans that integrate biological information regarding population dynamics and factors that influence their survival. This study documented infants born to wild cotton-top tamarin females from 1994-2008 at two distinct field sites in northern Colombia. Our studies have shown that wild cotton-top tamarins typically give birth to one litter each year and infant survival to 6 months of age was greater in the wild than has been reported in captive colonies. However, similar to reports from captive colonies, litter size of wild cotton-top tamarins ranges from 1-3 infants, with twin litters most common. Here we report the first occurrence of triplet litters in nearly 20 years of observing wild cotton-top tamarin groups. Over the first 3 months of life, wild-born infants exhibited highest mortality during the first week of life, similar to reports from captive colonies. Infant survival in the wild also increases with successive litters as it does in captivity. However, inter-birth interval, group size, and the number of adult males in the group did not appear to influence infant survival in the wild. The value of such long-term data from field studies aids in the information that can be used to model future population trends and develop effective conservation plans for this critically endangered primate.

Reproduction of Cubaris murina (Crustacea: Isopoda) under laboratory conditions and its use in ecotoxicity tests

Reproduction of the isopod Cubaris murina was studied in the laboratory in order to observe the offspring number per brood, the number and duration of the incubation periods, and the influence of repeated mating on number of young per brood. An experiment was conducted with two different groups: female/male pairs and females that were isolated after mating. No significant difference was found between the two reproductive female groups for the mean number of young per brood (x = 25) and the duration of the incubation periods (x = 17 days). One mating was enough for at least five broods, with no reduction in brood size. There was no significant difference between the number of adult males and females. Low-density cultures had a significantly higher growth rate compared to high-density cultures. Furthermore, the experimental results for optimization isopod culture conditions for terrestrial ecotoxicity testing are reported.

Intergroup conflicts among chimpanzees in Taï National Park: lethal violence and the female perspective

Intercommunity aggression in chimpanzees and primitive warfare in humans possess striking similarities, such as the common occurrence of large male coalitions, systematic control of territory boundaries, and lethal attacks on isolated individuals from neighboring groups. However, an important apparent contrast is the absence of recurrent peaceful interactions between neighboring groups of chimpanzees. We observed a remarkable range of behavior in intergroup encounters among three habituated communities of chimpanzees in Taï National Park, Côte d'Ivoire. Lethal attacks are documented in these study groups for the first time, as well as year-long exchanges of parous adult females and peaceful intergroup visits of mothers with infants. Demographic factors, including group size and number of adult males, are shown to affect the nature of intergroup interactions in ways not considered previously. A reconsideration of the difference in intergroup interactions between eastern and western chimpanzees is proposed including a more important consideration of the female's perspective. The inclusion of the new complexities in intergroup interactions in chimpanzees allows new parallels to be drawn with the evolution of primitive warfare in humans.

Effects of the Insecticide Phosmet on Solitary Bee Foraging and Nesting in Orchards of Capitol Reef National Park, Utah

Capitol Reef National Park, in southcentral Utah, contains 22 small orchards planted with antique fruit varieties by Mormon pioneers beginning over a century ago. The orchards continue to be managed in a pick-and-pay program, which includes spraying with phosmet to suppress codling moth (Cydia pomonella L.). The park is also home to a rich diversity of flowering plants, many of which are rare, bee-pollinated, and have populations within 1 km of the orchards. Over 3 yr, we studied the short-term effects of phosmet spraying on bee populations: (1) foraging on plants within the orchard understory and adjacent to it; and (2) nesting in, and at several distances from, the orchards. We recorded a rich bee fauna (47 taxa) in the orchards and on plants nearby. In 2 yr (2002 and 2004), we found no difference in the number of native bee visits to several species of plants flowering in and near to orchards immediately before and 1 d after spraying. Conversely, our nesting studies using the semidomesticated alfalfa leafcutting bee, Megachile rotundata (F.), showed strong significant declines in the number of adult males, nesting females, and progeny production subsequent to spraying at distances up to 160 m from sprayed orchards where the bees were presumably foraging. We showed that M. rotundata is negatively affected by phosmet spraying and suggest that caution should be exercised in its use in areas where bees are apt to forage.

Effects of the Insecticide Phosmet on Solitary Bee Foraging and Nesting in Orchards of Capitol Reef National Park, Utah

Capitol Reef National Park, in southcentral Utah, contains 22 small orchards planted with antique fruit varieties by Mormon pioneers beginning over a century ago. The orchards continue to be managed in a pick-and-pay program, which includes spraying with phosmet to suppress codling moth (Cydia pomonella L.). The park is also home to a rich diversity of flowering plants, many of which are rare, bee-pollinated, and have populations within 1 km of the orchards. Over 3 yr, we studied the short-term effects of phosmet spraying on bee populations: (1) foraging on plants within the orchard understory and adjacent to it; and (2) nesting in, and at several distances from, the orchards. We recorded a rich bee fauna (47 taxa) in the orchards and on plants nearby. In 2 yr (2002 and 2004), we found no difference in the number of native bee visits to several species of plants flowering in and near to orchards immediately before and 1 d after spraying. Conversely, our nesting studies using the semidomesticated alfalfa leafcutting bee, Megachile rotundata (F.), showed strong significant declines in the number of adult males, nesting females, and progeny production subsequent to spraying at distances up to 160 m from sprayed orchards where the bees were presumably foraging. We showed that M. rotundata is negatively affected by phosmet spraying and suggest that caution should be exercised in its use in areas where bees are apt to forage.

Adult Male Circumcision

Circumcision generally is performed during the newborn or adolescent period. An estimated one in six newborn males is circumcised worldwide. In 1992, a reported 60% of male newborns were circumcised in the United States. The exact number of adult males circumcised, however, is not known. Adult male circumcision occurs for multiple reasons, which include medical, social, religious, and personal. 1

The impact of sport-hunting on the population dynamics of an African lion population in a protected area

Between 1999 and 2004 we undertook an ecological study of African lions ( Panthera leo) in Hwange National Park, western Zimbabwe to measure the impact of sport-hunting beyond the park on the lion population within the park, using radio-telemetry and direct observation. 34 of 62 tagged lions died during the study (of which 24 were shot by sport hunters: 13 adult males, 5 adult females, 6 sub-adult males). Sport hunters in the safari areas surrounding the park killed 72% of tagged adult males from the study area. Over 30% of all males shot were sub-adult (<4 years). Hunting off-take of male lions doubled during 2001–2003 compared to levels in the three preceding years, which caused a decline in numbers of adult males in the population (from an adult sex ratio of 1:3 to 1:6 in favour of adult females). Home ranges made vacant by removal of adult males were filled by immigration of males from the park core. Infanticide was observed when new males entered prides. The proportion of male cubs increased between 1999 and 2004, which may have occurred to compensate for high adult male mortality.

Effects of group size on birth rate, infant mortality and social interactions in Formosan macaques at Mt Longevity, Taiwan

In social animals, the influence of life-history traits on group structure and size is potentially important in the context of the evolution of social systems. Birth rate and infant survival have been differently predicted as a function of group size by models of the evolution of group living in primates. A wild population of the Formosan macaque, Macaca cyclopis that inhabits Mt Longevity, Taiwan has been monitored since July 1993 to collect demographic, reproductive and social behaviour data. Little is known about the effects of troop size on population growth in Formosan macaques. In this paper, we have presented for the first time 5-years of data (1997–2001) on the troop dynamics of 14 social troops. We also examined the effects of troop size on birth rate, infant mortality and inter-troop social interactions. The annual average troop size increment fluctuated from 1.94% to 10.97%. The annual average troop size of 14 groups was 43.57 ± 15.88 individuals in 1997, and increased to 55.97 ± 16.86 individuals in 2001. The per-capita rates of troop size increase was negatively correlated with troop size without infants (F1,12 = 5.57, P < 0.05). The average birth rate (birth per adult female) was 0.78 (± 0.07, n = 14) and it was not linearly related to troop size, nor the number of adult females (P > 0.33). The average infant mortality was 0.16 (± 0.09, n = 14), which was relatively constant regardless of the troop size category (small, medium or large). Intertroop dominance was closely dependent on the number of adult males and females rather than group size. Thus larger group size imposed an advantage on habitat utilization without the appearance of low birth rate or high infant mortality. On the other hand, infant mortality increased and infant survival per adult female decreased when the percentage of adult females increased in troops. Therefore, competition among adult females plays an important role partially supporting the predation — intra-group feeding competition hypothesis.

Genetic relationships between indicator traits and nematode parasite infection levels in 6-month-old lambs

This study investigated traits that could be used to aid selective breeding for increased nematode resistance in sheep. Data were collected on approximately 1000 Scottish Blackface lambs over a 5-year period (1992–6). The animals were continually exposed to mixed nematode infection by grazing. Anthelmintic treatment was administered and blood samples were collected every 28 days from 4 to 24 weeks of age. Approximately 500 of the lambs were necropsied at 6 to 7 months of age and their worm burdens were recorded. The traits measured were the number of adult males, adult females, fifth-stage larvae and fourth-stage larvae for all species present. In addition, the mean length of adult females and the number of eggs in utero were estimated forTeladorsagia circumcincta. Several indicator traits were also measured on some of the animals, including : faecal egg counts, immunoglobulin A activity and eosinophil count as markers of the local immune response, and plasma pepsinogen activity and fructosamine concentration as indicators of the pathological consequence of infection. The heritabilities for worm length, eggs in utero and worm burden were 0.53±0.17, 0.50±0.16 and 0.13±0.10 respectively. At a mean age of 22 weeks the heritabilities for fructosamine concentration, IgA activity, eosinophil count and pepsinogen activity were 0.39±0.16, 0.57±0.15, 0.35±0.15 and 0.56±0.16 respectively. Strong negative genetic correlations (&lt; −0.6) were often observed between necropsy traits and eosinophil count, IgA activity and pepsinogen activity. Substantial genetic correlations were also observed between fructosamine concentration and worm length (0.67) and number of fourth-stage larvae (−0.80). The genetic and environmental correlations between indicators and necropsy traits were often opposite in sign. The indicator traits studied could aid selection for increased resistance to gastrointestinal nematodes in sheep.

Constraints on control: factors influencing reproductive success in male mandrills (Mandrillus sphinx)

Over the last decade, paternity analysis using molecular markers has revealed that observed mating systems do not necessarily correlate with reproductive systems and thus cannot provide reliable information about male reproductive success (RS). This is especially true for primate species with a complex multimale-multifemale social organization, such as mandrills (Mandrillus sphinx). Using molecular markers for the measurement of individual RS and a comprehensive data set comprising 193 offspring from 27 birth cohorts over a 20-year period of sampling, we investigated the social, genetic, and demographic factors that may influence the probability of paternity by dominant male mandrills, living in a semi–free-ranging colony. We observed a significant skew in RS towards dominant males, with their probability of paternity increasing as the number of adult males in the group increased, and when they were closely related to subordinate adolescent males. Conversely, the probability of dominant males siring infants decreased when the number of simultaneously tumescent females increased. Fewer offspring were sired by dominant males when female partners were closely related to them and when the relatedness between dominant and subordinate adult males increased. These two last points suggests particularly that mechanisms of kin recognition are operating to avoid the costs of inbreeding and may also reflect the lower costs to dominant males of losing conception opportunities to more closely related subordinate adult males. This study is, to our knowledge, one of the first in primates to use an integrative approach and multivariate analysis to show that multiple factors are involved in determining the probability of paternity by dominant males.

REPRODUCTIVE BEHAVIOR IN FEMALE IBERIAN RED DEER: EFFECTS OF AGGREGATION AND DISPERSION OF FOOD

Resource dispersion influences mammalian mating systems by affecting space use by females and in turn the strategies employed by males. Other elements related to mating interactions, however, also may affect female decisions, and it usually becomes difficult to discriminate between them. Here we present the results of experimental food supplementation during rut in the red deer (Cervus elaphus hispanicus). We provided food at 2 levels of spatial dispersion in order to test whether changes in the distribution of food within a short period of time affect spatial behavior of females or other features of the mating system. Food clumping produced an increase in local density of females using an area and in the size of female groups. It also produced an increase in number of adult males, male–male interactions, and male harassment toward females. Despite the overall rate of harassment being higher with food clumping, females received a lower per capita rate of harassment because they gathered into much larger harems. Variance in harem size increased with higher levels of food clumping. Our data show that females were highly sensitive to food distribution when joining harems, which stresses the relative importance of direct benefits (food and sexual harassment avoidance) in molding the conditions under which selection operates during rut in Iberian red deer.

REPRODUCTIVE ECOLOGY AND MATING SUCCESS OF MALE LIMNONECTES KUHLII, A FANGED FROG FROM TAIWAN

The reproductive ecology and mating success of male Limnonectes kuhlii, one of the fanged frogs which are characterized by a suite of unusual sexually dimorphic traits (males have larger body, head, and fang sizes than females), were studied under natural conditions in subtropical Taiwan in order to clarify the role of sexual selection on male body size. There were no significant temporal peaks in the number of adult males or amplexed females observed along an 81-m transect of a small creek throughout a 3-mo study period. The nightly sex ratio was highly male biased. Over the study period, the distribution pattern of males showed a significant tendency toward clumping at oviposition sites (represented as oviposition sections of the creek where females laid eggs). During the nights, males usually showed a nonclumped distribution pattern along the transect, probably due to male-male interactions mediated through vocalization and physical combat, including vigorous biting. The calling sites of males were con...

Demographic Variation Among Udzungwa Red Colobus in Relation to Gross Ecological and Sociological Parameters

We evaluated variation in group size and composition of Udzungwa red colobus (Procolobus gordonorum) in relation to gross-habitat and sociological parameters. The endangered species is endemic to the Udzungwa Mountains and nearby forests in the Kilombero Valley of south-central Tanzania. We counted 63 groups in 10 forests, ranging in altitude from 250 to 1,800 m. Group size ranged from 7 to 83 (x = 36.3) individuals and adult sex ratios (females/male) ranged from 1.5 to 7.3 (x = 3.5), excluding solitary individuals. Group size was influenced by several habitat parameters, including tree density, degree of deciduousness, and forest size. Groups were largest in large blocks of mature, moist, mixed evergreen and semideciduous forests, but group size is not correlated with altitude. Groups in a highly degraded forest appeared to have fission-fusion societies. The effect of habitat quality on age-sex composition of groups was most apparent in natality and less so in survivorship of adult females and juveniles. The number of adult males in groups accounted for 50% of the variance in group size and 34–39% of the variance in numbers of adult females in groups. Habitat quality affects natality more than demographic parameters do. Groups with a low proportion of adult females had greater juvenile survivorship, perhaps because of lower food competition between these two classes. We proffer hypotheses based on our study and previous intertaxonal comparisons to explain cause and effect relationships between habitat quality and demography. Finally, our study demonstrates the importance of large blocks of old-growth forest to the conservation of Udzungwa red colobus, and we make recommendations for conservation and research.

Social influences on ranging patterns among chimpanzees (Pan troglodytes verus) in the Tai National Park, Cote d'Ivoire

Group size is expected to be an important factor to predict home-range (HR) size in social animals. In chimpanzees adult males play an important role in defending the HR against neighbors, and therefore it has been suggested that HR size depends on the number of adult males. In this long-term study on wild West African chimpanzees, we analyzed the relative importance of community size and composition on ranging patterns over a 10-year period, using multivariate statistics. Because community size decreased from 51 individuals with 6 adult males in 1992 to 22 individuals with only 1 adult male in 2001, we expected a decrease in HR size, which should be better predicted by the number of males than by community size. We further investigated the effect of fruit availability on monthly HRs over a 4-year period. As predicted, HR size decreased during the first 7 years of our study but increased during the last 3 years. Overall, the number of adult males was the best predictor of HR size, whereas fruit availability did not correlate with HR size. HR use remained stable over the entire study period, with a constant proportion of about 35% of the HR used as core area. High HR and core-area overlap values between different years indicated strong site-fidelity. Although the number of males within the community explained the decrease in HR size, the recent increase in size remains unexplained. This finding suggests that other factors such as relative fighting power of males affect HR size. Copyright 2003.

Population density and group composition of Japanese sika deer (Cervus nippon yakushimae) in an evergreen broad‐leaved forest in Yakushima, southern Japan

The population density of Japanese sika deer (Cervus nippon yakushimae Kuroda and Okada) in an evergreen broad‐leaved forest in Yakushima, southern Japan, was surveyed over 4 years from 1998 to 2001. Two approximately 50 ha study sites, Hanyama and Kawahara, were established with a total of 4 km of census trails at each site. The estimated densities of sika deer at the two sites were 43–70 deer km−2 at Hanyama and 63–78 deer km−2 at Kawahara, although these values might be underestimates. The adult sex ratio (number of adult males : number of adult females) ranged from 0.6 to 1.0 at Hanyama, and from 0.4 to 0.9 at Kawahara. Mean group size was 1.9 deer (male group, 1.5 deer; female group, 1.6 deer; mixed group, 3.6 deer). The population density of sika deer was relatively high compared to other sites in Japan, with the exception of very small (&lt;10 km2) islands. Possible explanations for this naturally high density of sika deer in an evergreen broad‐leaved forest in Yakushima are discussed.

Variability in adult group compositions of a prosimian primate

Many species fall into specific mating-system categories, and that category is usually associated with a suite of behavioral and morphological characteristics. Several lemur species, including Propithecus diadema edwardsi, have been labeled "idiosyncratic" because variation in socionomic sex ratios among groups is consistent with wide variation in social structure. We used several hypotheses founded in behavioral ecology to assess variability in P. d. edwardsi. First we examined 46 group-mating seasons to quantify variability. We then tested predictions that the number of males per group would increase as the number of adult females increased, and the number of males would increase as female mating synchrony increased. Examining variation in offspring survival relative to the number of adult males in a group may tell us which composition is likely to persist into the future, so we also hypothesized that as the number of males in a group increased, fertility and offspring survival would increase. We found an equal distribution of polygynous, polygynandrous, pairs, and polyandrous groups. Furthermore, female distribution and mating synchrony did not predict the number of males, and offspring survival was not correlated with the number of males. Since infants survived equally well in groups of all compositions, sifakas experienced no pressure to maintain a particular number of adult males per adult female. The small number of adults per group (mean=3.2) may result from balancing feeding competition against predator detection. Augmenting the mate pool available from the group with mates from neighboring groups may promote the notable variability seen in the adult group compositions of sifakas.

Conservation: Reproductive collapse in saiga antelope harems.

A common assumption is that breeding in polygnous systems is not limited by the number of males because one male can inseminate many females1,2. But here we show that reproductive collapse in the critically endangered saiga antelope (Saiga tatarica tatarica) is likely to have been caused by a catastrophic drop in the number of adult males in this harem-breeding ungulate, probably due to selective poaching for their horns. Fecundity and calf survival are known to be affected by markedly skewed sex ratios3, but in the saiga antelope the sex ratio has become so distorted as to lead to a drastic decline in the number of pregnancies — a finding that has implications both for the conservation of the species and for understanding the reproductive ecology of polygynous ungulates.

Spatial Distribution of Cattle Herds as a Response to Naturaland Social Environments: A Case Study from the Zamfara Reserve, Northwest Nigeria

Introduction Cattle are the basis of livelihood for pastoralists and agropastoralists in the northern parts of West Africa. They are used for milk, manure, meat and draught power, and they serve as savings and insurance. The composition of pastoral herds, particularly cattle, has often been analysed. Usually, the sex and age groups of individual herds, counted directly or assessed from interviews with the owner or herder, are recorded. Conclusions are then drawn from the herd structure on breeding and commercial strategies, as well as on the main goals of production and market integration. Results indicate that these parameters vary, depending on the specialisation of production in ecological niches or regions (Amanor 1995; FDLPCS 1992a, b; Sutter 1987; Vabi 1993). Cattle herds in the arid parts of West Africa are more specialised in the production of young stock, and their owners are mainly nomadic pastoralists. The herds contain a high percentage of reproductive females (over 45 percent), with a calving rate higher than 60 percent, and a commercial off-take of at least 11 percent. To lower mortality in a risky environment, these pastoralists sell young stock, particularly males, under the age of three. In contrast, herds in the semi-arid parts of West Africa belong to transhumant pastoralists or agropastoralists. Living in a more resource-endowed and less risky environment, such herds have a lower percentage of reproductive females (30-40 percent), a low calving rate, and a larger number of adult males over the age of six (24-63 percent). Besides milk, the production of mature males of heavy weight is a production goal that is related to favourable conditions of pasture and water and the farmers' demand for draught animals (Amanor 1995; Vabi 1993). Data on livestock numbers are generally hard to obtain in northern Nigeria. Collecting data on herd size by counting or interviews is problematic. First, pastoralists are reluctant to give information about their livestock numbers, partly due to cultural reasons and partly for fear of taxation (Gefu 1992; Mohammed and Bello 1994). Secondly, management practices to cope with risk in an ecologically and economically highly variable environment exacerbate the problems of getting accurate data on livestock ownership. Such practices lead to an overlapping of ownership and management patterns, hence, the term 'herd' applies to the unit of management, rather than to that of ownership. This is due to: * the widespread exchange of animals within a social network; * the splitting of herds into management units which might be herded far away from the owner's homestead; * the herding of animals of different (absentee) owners in one herd; * and the hired herder's reluctance to admit to being just a 'poor' employee who has to herd for others. This study attempts to describe size and composition of the herds counted along transects on natural range. Counting domestic livestock gives no information on ownership patterns, but provides information on herding management on a spatial scale and on the existing stocking density. The method of animal ground counts along transects had been established mainly in the field of wildlife studies for the assessment of game populations in inaccessible areas (Norton-Griffiths 1978). It is hoped that this provides some insights regarding herd management in a forest reserve in northern Nigeria. The Study Site The Zamfara Forest Reserve (6[degrees]30' to 7[degrees]15'E, 12[degrees]10' to 13[degrees]05'N) is located in the north of Zamfara State, which shares borders with the Republic of Niger to the north, Sokoto State to the west and Katsina State to the east (Figure 1). Annual rainfall ranges from 500 mm in the north to 850 mm in the south with considerable inter-annual variations (CV 22 to 32 percent). The vegetation is of a northern Sudan savannah type. [FIGURE 1 OMITTED] In 1919 the area was declared a forest reserve by the British, and it became unlawful to pasture domestic herbivores or cultivate the soil (Forestry Law of 1938, 1963 version). …

Population responses of the freshwater amphipod Gammarus pulex (L.) to an environmental estrogen, 17α‐ethinylestradiol

The effects of the environmental estrogen 17alpha-ethinylestradiol (EE) on mixed populations of 90 individual Gammarus pulex were examined following a 100-d exposure in a flow-through system. Counts of total animal numbers revealed that, in all treatment groups, population size dramatically increased due to recruitment, with neonate and juvenile gammarids the most abundant. At concentrations of 1 and 10 microg/L EE, the recorded mean population sizes of 385 and 411, respectively, were significantly greater (p = 0.018) than the control (169). Mean population sizes in the solvent control (257) and 100 ng/L EE treatment (267) were not significantly different (p > 0.05) from the control. In addition to total counts, detailed image analysis of each individual animal allowed the assessment of length-frequency distributions, adult sex ratio, number of precopula pairs/ovigerous females, and measurement of secondary antenna and gnathopod length (secondary sex characteristics). The sex ratio of adults at 100 ng, 1 microg, and 10 microg/L EE was greater than 2:1 (female:male), and significantly more females (p = 0.008) were recorded at these concentrations compared with the control. The number of male adults, precopula guarding pairs, and ovigerous females did not differ between treatments (p > 0.05). Secondary antennal and gnathopod length in males was consistently greater than in females (p < or = 0.001), but comparison between groups revealed no difference in these parameters.