Mechanical response of the tympanal membranes of the tree cricket <Emphasis Type="Italic">Oecanthus henryi</Emphasis>

Crickets have two tympanal membranes on the tibiae of each foreleg. Among several field cricket species of the genus Gryllus (Gryllinae), the posterior tympanal membrane (PTM) is significantly larger than the anterior membrane (ATM). Laser Doppler vibrometric measurements have shown that the smaller ATM does not respond as much as the PTM to sound. Hence the PTM has been suggested to be the principal tympanal acoustic input to the auditory organ. In tree crickets (Oecanthinae), the ATM is slightly larger than the PTM. Both membranes are structurally complex, presenting a series of transverse folds on their surface, which are more pronounced on the ATM than on the PTM. The mechanical response of both membranes to acoustic stimulation was investigated using microscanning laser Doppler vibrometry. Only a small portion of the membrane surface deflects in response to sound. Both membranes exhibit similar frequency responses, and move out of phase with each other, producing compressions and rarefactions of the tracheal volume backing the tympanum. Therefore, unlike field crickets, tree crickets may have four instead of two functional tympanal membranes. This is interesting in the context of the outstanding question of the role of spiracular inputs in the auditory system of tree crickets.     

A Comparison of Female Mating Strategies in <Emphasis Type="Italic">Pan troglodytes</Emphasis> and <Emphasis Type="Italic">Pongo</Emphasis> spp.

Orangutans and chimpanzees differ in many aspects of their mating and social systems. Nevertheless, because both great apes require enormous maternal investment in offspring and because female reproductive potential is limited, female orangutans and chimpanzees should be selective of their mates, yet expected to exhibit anti-infanticide strategies such as mating with multiple males. We review and compare mating patterns in orangutans and chimpanzees to understand how these critical pressures are filtered through the different demands of the socioecology of each species. We highlight the variation in female mating behavior as a function of the proximity of ovulation. We conclude that both genera pursue tactics for paternity confusion by mating with multiple males and by mating cooperatively or even proceptively with nonpreferred partners when conception is unlikely. Mating selectivity is suggested by variation in proceptive behavior toward particular partners and by increased resistance of nonpreferred partners during the periovulatory period. Thus, data for both species support a mixed mating strategy whereby females shift their mating behavior in accordance with ovulatory status to accommodate the competing demands of mate selectivity and paternity confusion.     

Female-directed Male Aggression in Wild <Emphasis Type="Italic">Ateles geoffroyi yucatanensis</Emphasis>

Male spider monkeys direct the majority of their aggression toward adult females, and the aggressive interactions may be a form of sexual coercion. We investigated female-directed male aggression in 2 wild communities of spider monkeys (Ateles geoffroyi yucatanensis) from the Otoch Ma’ax Yetel Kooh Reserve in Yucatan, Mexico to evaluate the sexual coercion hypothesis. The aggression occurred in 2 distinct forms: physical aggression and prolonged noncontact chases. The latter appeared highly ritualized in nature and accounted for >80% of all female-directed male aggression. Rates of prolonged chases, but not physical aggression, peaked when the female target was likely cycling and were associated with male place-sniffing of the substrate previously occupied by the female target. Prolonged chases were also associated with proceptive behavior directed from the female target toward her male attacker after the chase had ceased. Our data therefore suggest that prolonged chases are sexually motivated. Prolonged chases did not result in immediate copulation, but sometimes the female victim left the subgroup to travel alone with her male aggressor, and thus prolonged chases may be a form of male intimidation to coerce females into a mating consortship. However, as prolonged chases appeared highly ritualized, the chases may also be a form of male sexual display. Further investigation of the costs incurred by female recipients of prolonged chases is therefore required before one can interpret the behavior as sexual coercion.     

Female Choice and the Consistency of Courtship Feeding in Black-horned Tree Crickets Oecanthus nigricornis Walker (Orthoptera: Gryllidae: Oecanthinae)

Courtship feeding in insects is often strongly correlated with insemination duration and therefore provides a potential postcopulatory episode of sexual selection. We tested whether courtship feeding and other courtship traits in the black-horned tree cricket Oecanthus nigricornis showed sufficient consistency potentially to respond to sexual selection by testing whether they differed significantly among males. Duration of courtship feeding differed among males when measured repeatedly and this caused significant differences in the duration of spermatophore attachment, a trait that determines the maximum duration of insemination and thus has important fitness consequences in crickets. We also partitioned variance in courtship behaviour between the sexes to test whether differences in courtship behaviour were attributable primarily to males, females or both sexes. Duration of spermatophore attachment was controlled by females and therefore represents a mechanism of female mate choice. Significant variation in duration of spermatophore attachment was associated with differences between individuals of both sexes. Differences among males indicate that females agree in their preference of certain males whereas differences among females indicate that females differ in their receptivity to postcopulatory courtship and insemination. The fact that differences among males in duration of spermatophore attachment were due to significant differences solely in the period of courtship feeding indicates that postcopulatory female choice was mediated through courtship feeding. Whether males manipulate female choices by allocating more or fewer resources requires further testing, but we found that males court some females more vigorously than others after females dismount. The number of previous mates had opposite effects on the duration of courtship feeding for the sexes, decreasing it for males but increasing it for females, and we discuss the possible causes of these results.     

Evidence of Monandry in a Mosquito (<Emphasis Type="Italic">Sabethes cyaneus</Emphasis>) with Elaborate Ornaments in Both Sexes

Despite the benefits of multiple mating to females many mosquitoes appear to be monandrous. Members of the mosquito tribe Sabethini are unique among the mosquitoes for they possess iridescent scales and elaborate ornaments in both sexes. Additionally, this tribe boasts the only reported cases of courtship display within the mosquitoes. Due to these singular traits and behaviors, we predicted that members of this tribe have a different mating system with relatively high female mating rate. We tested this prediction in the ornamented mosquito Sabethes cyaneus. Contrary to our prediction, however, females were monandrous throughout their lifetime and multiple gonotrophic cycles. We discuss the possible implications of monandry on the evolution of sexually homologous ornaments, with particular consideration of mutual mate choice.     

The complete mitochondrial genome of <Emphasis Type="Italic">Deracantha onos</Emphasis> (Orthoptera: Bradyporidae)

The complete mitochondrial genome 15,650 bp in size of the Deracantha onos has been determined. The gene content, base composition and codon usage of D. onos are coincident to typical hexapods mitochondrial genomes. Genes arrangement of D. onos is identical to Gryllotalpa orientalis, Ruspolia dubia and Anabrus simplex, in that the relative locations of tRNA^Lys and tRNA^Asp was different to that of Locusta migratoria. All tRNAs could be folded into the typical cloverleaf secondary structure, excluding tRNA^Ser(AGN) which forms another structure according to the Steinberg–Cedergren tertiary structure. Sequence analysis of the A + T-rich region with Dot-plot did not find any conspicuous repeat clusters. Two poly-thymine (poly-T) nucleotide stretches of 20 bp and 11 bp in size, which may involved in the recognition of replication origin, were found on the H-strand and L-strand in the A + T-rich region of the D. onos mitogenome, respectively. One open reading frame (ORF) 87 amino acids in size was found on the H-strand, but Protein Blast searches analysis indicated that it was a nonfunctional ORF.     

Mating behavior in the ant, <Emphasis Type="Italic">Myrmecina graminicola</Emphasis> (Myrmicinae)

Summary Sexual behavior of Myrmecina graminicola in laboratory conditions is described. Virgin females, both gynomorphs and intermorphs, exhibit an inconspicuous "sexual calling", apparently depositing a sex pheromone on the substrate close by. The sexual pheromone is produced in the poison gland. Copulation needs between 40 and 60 seconds, dealation of gynomorphs follows soon after. Some observations are in marked contrast to former reports, e.g. on duration of copulation in M. graminicola (Donisthorpe, 1927: several hours) and on the source of a sex pheromone in the closely related M. nipponica (Murakami et al., 2002: pygidial gland).Received 4 February 2003; revised 19 May 2003; accepted 19 May 2003.     

Sociality in <Emphasis Type="Italic">Euglossa</Emphasis> (<Emphasis Type="Italic">Euglossa</Emphasis>) <Emphasis Type="Italic">viridissima</Emphasis> Friese (Hymenoptera,Apidae, Euglossini)

Euglossa viridissima is an orchid bee that forms both solitary and multiple female nests, making it a suitable species for the study of factors leading to diverse degrees of sociality in Euglossines. We conducted observations in eight reused nests (where a first generation of bees had been produced) kept in artificial boxes from the Yucatan Peninsula, Mexico. Five nests were reused (reactivated) by a single female (SFN), two nests reused by a mother and one daughter (MFN1) and one nest reused by the mother and two daughters (MFN2). No single nest was reactivated by unrelated females. The number of foraging trips, their duration and the duration of cell provisioning was not different between SFN and MFN. The overall production of cells per female was not different either between both types of nest. However, in MFN although all females did lay eggs, there was a reproductive skew in favor of the mother (95 and 45% of the brood produced in MFN1 and MFN2 respectively). She showed reproductive control of her daughters through oophagy and displaying threatening behavior when the daughters tried to open a cell where she had laid an egg. Brood losses to parasites (Anthrax sp. (Bom-byliidae) and Hoplostelis bivittata (Megachilidae)) were only found in SFN which possibly reflects and advantage of MFN in this respect. Our results coupled with other studies in Euglossa, reveal that a wide range of social behaviors occur in this genus, from solitary and communal to primitive reproductive division of labor. Multiple factors involving different levels of pressure imposed by food availability and parasites may favor such a diverse range of nesting behaviors. Interestingly, female associations in E. viridissima seem a result of kin selection that is enforced by coercion from mother females on their daughters. More studies are needed to shed light upon the social organization of Euglossa and other Euglossines and on their phylogenetic relationships in order to trace the origins of eusociality in Apidae. Received 12 February 2008; revised 25 June 2008; accepted 17 July 2008.     

The Mating System of <Emphasis Type="Italic">Amegilla</Emphasis> (<Emphasis Type="Italic">Asarapoda</Emphasis>) <Emphasis Type="Italic">paracalva</Emphasis> Brooks (Hymenoptera: Apidae)

Males of the solitary bee Amegilla (Asarapoda) paracalva employ two mate-locating tactics: aggressive defense of sites from which virgin females are emerging and patrolling flower patches that are visited by conspecific females. At one study site, a single male was able to control an entire emergence area for one or more days. Multiple males patrolled one flower patch, interacting aggressively on occasion but no one individual was able to monopolize this resource. Territorial males at the emergence site secured mates by waiting by tunnels for receptive virgin females to emerge after metamorphosis. Males patrolling the flower patch pounced upon flower visiting conspecifics and mated with receptive females there. Territorial males at the emergence site were larger than average individuals, probably because of the advantage larger males have when grappling with opponents. Flower patrolling males were smaller than territorial males at the emergence sites, perhaps because of the advantages gained by these males from rapid, agile flight.     

The Effects of Age and Previous Mating Experience on Pre- and Post-copulatory Mate Choice in Female House Crickets (<Emphasis Type="Italic">Acheta domesticus</Emphasis> L.)

Although females’ mating preferences are influenced by male characteristics, there are a number of factors intrinsic to females and unrelated to male phenotype that can modulate female choice. We assessed the effects of age and mating experience on mechanisms of pre- and post-copulatory mate choice in female house crickets, Acheta domesticus L., by randomly assigning males to females, but independently varying the age and number of previous matings of females at the time of experimental matings. Latency to mating, a measure of a female’s pre-copulatory preference, was influenced by female age at the time of mating, with older females mating sooner than younger females. The reduced selectivity of older females appears consistent with life-history theory, which predicts that the reproductive value of females should decline with age. The length of time that females retained the spermatophore after mating, a measure of a female’s post-copulatory mating preference, was not influenced by female age at the time of mating, the number of previous matings, or any interaction between the two main effects. Contrary to previous reports, male mass had no effect on either the latency to mating or female retention of the spermatophore in A. domesticus. We conclude that female age and mating experience can moderate female selectivity, but that their impact varies according to the mechanism by which females favor particular sires.     

New combinations and typifications in <Emphasis Type="Italic">Bistorta</Emphasis>, <Emphasis Type="Italic">Persicaria</Emphasis>, <Emphasis Type="Italic">Polygonum,</Emphasis> and <Emphasis Type="Italic">Rumex</Emphasis> (Polygonaceae)

New combinations are proposed in anticipation of the Polygonaceae treatment in the forthcoming volume of Intermountain Flora: Polygonum kelloggii var. esotericum, P. kelloggii var. watsonii , Rumex densiflorus var. pycnanthus , R. salicifolius var. utahensis, and R. occidentalis var. tomentellus. Typifications are proposed to facilitate ongoing studies in Polygonaceae and to maintain current usage.     

Familiarity and partner preferences in female common voles, <Emphasis Type="Italic">Microtus arvalis</Emphasis>

Captive female common voles (Microtus arvalis) had a clear social preference for familiar males in a standard preference test. Cohabitation for a short period resulted in preferences for familiar partners, and females spent eight times more time in body contact with a familiar male than with an unfamiliar male. Females also displayed stranger-directed aggression. Our results suggest that the common vole is a species with selective partner preferences and a tendency to form tight social relationships and stable male–female associations.     

<Emphasis Type="Italic">Ty</Emphasis>1<Emphasis Type="Italic">/copia</Emphasis>- and <Emphasis Type="Italic">Ty</Emphasis>3<Emphasis Type="Italic">/gypsy</Emphasis>-like DNA sequences in <Emphasis Type="Italic">Helianthus </Emphasis>species

Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes.     

Persistence of <Emphasis Type="Italic">Paranosema</Emphasis> (<Emphasis Type="Italic">Nosema</Emphasis>) <Emphasis Type="Italic">locustae</Emphasis> (Microsporidia: Nosematidae) among grasshopper (Orthoptera: Acrididae) populations in the Inner Mongolia Rangeland,China

Paranosema (Nosema) locustae Canning has persisted in grasshopper populations in the Inner Mongolia Rangeland since spore treatment was applied in 1993. In the treatment year, a 58.32–71.43% reduction of grasshoppers was recorded and 59.26–80.36% of surviving grasshoppers of various species were infected. In the years following application, prevalence of P. locustae varied from 13.65% to 60.71%, demonstrating that P. locustae remains in grasshopper populations for many years. Infection prevalence was more than 60.00% for Dasyhippus barbipes (F.-W.), Bryodema luctuosum luctuosoma (Stoll) and Angaracris barabensis (Pall.) in 1993 but was very variable, ranging from 20.00% to 60.71% over the subsequent nine years. Disease prevalence was 43.72–60.71% in 1993 and 1994 for Oedaleus asiaticus B.-Bienko and Myrmeleotettix palpalis (Zub.) but gradually declined to approximately 20%, where it remained. Persistence of P. locustae in grasshopper populations may be important in keeping densities below economic thresholds for a number of years after application. Handling Editor: Helen Roy.     

Pre- and Post-Copulatory Mate Selection Mechanisms in an African Dung Beetle, <Emphasis Type="Italic">Circellium bacchus</Emphasis> (Coleoptera: Scarabaeidae)

Females of most taxa mate selectively. Mate selection may be: (1) pre-copulatory, involving active female choice and male-male competition, and (2) post-copulatory, with cryptic female choice and sperm competition. Because female dung beetles (Circellium bacchus) invest heavily in parental care by ball-rolling and remaining with developing larva they are, therefore, expected to be highly selective when mating. Mate choice in this species was investigated via behavioral observations and investigations of genital allometry of both sexes, leading to conclusions about the mechanisms of, and male characteristics important in, female choice. Male–male competition seems to be crucial in mate selection of C. bacchus, although the females appeared to show no active mate choice. There is a negative allometric relationship between genital size and body size of males as predicted by the ‘one size fits all’ hypothesis (where males have genitalia that fit average-sized females). For the females, no relationship was found between genital size and body size. This might be as a result of the non-sclerotized nature of female genitalia, which may allow for greater morphological plasticity.     

Revision of the <Emphasis Type="Italic">Serrulati</Emphasis> species of <Emphasis Type="Italic">Penstemon</Emphasis> section <Emphasis Type="Italic">Saccanthera</Emphasis> subsection <Emphasis Type="Italic">Serrulati</Emphasis>

A revision of Penstemon sect. Saccanthera subsect. Serrulati includes a new species (P. salmonensis), a new variety (P. triphyllus var. infernalis), and the elevation of a subspecies to species (P. curtiflorus), bringing the total number of species to eight, which are keyed and described, complete with nomenclature and type citations.     

<Emphasis Type="Italic">Arthroderma benhamiae</Emphasis> (The Teleomorph of <Emphasis Type="Italic">Trichophyton mentagrophytes</Emphasis>) Mating Type-Specific Genes

This study first report to identify the mating type (−)-specific gene of alpha-box and the mating type (+)-specific gene of the high-mobility-group (HMG) DNA-binding domain in zoophilic dermatophytes of Arthroderma benhamiae in an effort to understand the epidemiological characteristics of Trichophyton mentagrophytes. The sequence of the alpha-box gene (1,387 bp) was found to contain two exons, from 184 to 475 bp and from 525 to 1,387 bp, coding a protein of 384 amino acids, beginning with a putative initiating methionine (ATG). The sequence of the HMG gene (1,910 bp) contained two exons, from 234 to 415 bp and from 479 to 1,457 bp, coding a protein of 386 amino acids, beginning with a putative initiating methionine (ATG).