WATERFOWL (ANATIDAE) ON IRRIGATION LAKES IN THE ORANGE FREE STATE

Geldenhuys, J. N. 1975. Waterfowl (Anatidae) on irrigation lakes in the Orange Free State. Ostrich 46:219-235.

The incidence and population size of fifteen duck species were determined on nine irrigation lakes in the Orange Free State, South Africa, during August 1972 to July 1973. Allemanskraal supported the highest average number of Egyptian Goose, South African Shelduck and Yellowbilled Duck. Redbilled Teal and Spurwinged Goose favoured Bloemhof. Cape Shoveller and Cape Teal concentrated on Kalkfontein, and Southern Pochard frequented Erfenis. The most common species were the Egyptian Goose, South African Shelduck, Yellowbilled Duck and Spurwinged Goose, in thit order according to average number of birds per count, Black Duck, Whitefaced Duck, Whistling Duck, Whitebacked Duck, Hottentot Teal, Knobbilled Duck and Maccoa Duck occurred sporadically. Relatively high seasonal population nuctuations were found in the South African Shelduck, Cape Teal, Southern Pochard and to a lesser extent in the Spurwinged Goose and Cape Shoveller.     

Minimal evidence of interspecific hybridisation between the Yellow-billed Duck and introduced Mallard in central and northwestern South Africa

Hybridisation is the interbreeding of genetically distinct groups that can lead to introgression – an exchange of genetic material between species. Hybridisation is of conservation concern when an alien invasive species is involved, as it can lead to a loss of local genetic adaptations and genetic diversity. Hybridisation is a significant threat for many dabbling ducks where interbreeding with the closely related invasive Mallard Anas platyrhynchos is extremely common. Phenotypic evidence suggests that Mallard populations in South Africa hybridise with the indigenous Yellow-billed Duck Anas undulata. The aim of this study was to determine the incidence of hybridisation between Yellow-billed Ducks, occurring in central and northwestern South Africa, and introduced Mallards. Genetic variation between Mallards, Yellow-billed Ducks, and their inferred hybrids was assessed using mitochondrial and microsatellite DNA markers. All samples inferred to be hybrids based on the phenotype were found to have Yellowbilled Duck mitochondrial DNA and showed minimal evidence of admixture across the microsatellite markers. Thus, these results do not support the notion that hybridisation between Mallards and Yellow-billed Ducks is prevalent in central and northwestern South Africa. However, hybridisation could be occurring where Mallards are found in higher abundance, such as in the Western Cape Province. Therefore, continued monitoring of this potential hybridisation should be performed frequently and throughout South Africa.     

Wing-flick Signals in the Courtship of the African Cave Cricket,Phaeophilacris spectrum

The male of the African cave cricket Phaeophilacris spectrum (Saltatoria: Grylloidea: Phalangopsidae) possesses tegmina without stridulatory organs, and both females and males lack tympanal organs. Therefore acoustic communication in the usual sense, which is typical for most crickets, is absent in this species. However, adaptations of the wing articulation allow the males to flick their wings forward over their heads. During courtship these movements are performed in series of 4–5 wing-flicks at a rate of 8–12 Hz (called wing-flick series = WFS) which elicit low-frequency air movements. Such signals may have taken over the functional significance of an acoustic ‘courtship song’. A quantitative analysis of the cricket's behaviour showed that in terms of frequency and total duration, ‘wing-flick series’ and ‘rocking’ behaviour are the most prominent signals of the male's courtship display. Moreover, analysis of the spatial relationships between male and female demonstrates that the wing-flicking is directed towards the female. The response of a female to a wing-flicking, courting male seems mainly to be calmed down and to reach a passive, receptive state, necessary for subsequent copulation. Females confronted with a male's courtship display exhibited a significantly higher threshold to disturbing stimuli than uncourted ones.     

MITOCHONDRIAL GENE TREES AND THE EVOLUTIONARY RELATIONSHIP OF MALLARD AND BLACK DUCKS

We assayed restriction site differences in mitochondrial DNA (mtDNA) within and among allopatric populations of the Mallard (Anas platyrhynchos) and the American Black Duck (A. rubripes). The observed mtDNA clones grouped into two phylogenetically distinct arrays that we estimate differ by about 0.8% in nucleotide sequence. Genotypes in one clonal array were present in both species, while genotypes in the other array were seen only in Mallards. In terms of the mtDNA “gene tree,” the assayed Mallards exhibit a paraphyletic relationship with respect to Black Ducks, meaning that genealogical separations among some extant haplotypes in the Mallard predate the species separation. Evidence is advanced that this pattern probably resulted from demographically based processes of lineage sorting, rather than recent, secondary introgressive hybridization. However, haplotype frequencies were most similar among conspecific populations, so the Mallard and Black Ducks cluster separately in terms of a population phenogram. The results provide a clear example of the distinction between a gene tree and a population tree, and of the distinction between data analyses that view individuals versus populations as operational taxonomic units (OTUs). Overall, the mtDNA data indicate an extremely close evolutionary relationship between Mallards and Black Ducks, and in conjunction with the geographic distributions suggest that the Black Duck is a recent evolutionary derivative of a more broadly distributed Mallard-Black ancestor.     

Temporal patterning of courtship behaviour in some parasitic Hymenoptera,with special reference to Melittobia acasta

In many parasitic hymenoptera copulation is preceded by elaborate courtship displays which include species-specific characteristics. Other features, shared by related species, may be used for defining higher taxa. The male's repertoire consists of movements involving the wings, legs, antennae, and mouthparts. These movements are performed continuously, or intermittently, depending on the species involved. The elements of a repertoire are repeated over and over again until the female indicates her readiness to copulate. Temporal patterning of various displays, and the timing of the female response are described. In Melittobia acasta (Walker) (Eulophidae) the male display is composed not only of repeating elements, but also includes new elements, introduced along the way; the display progresses towards a climactic finale. The timing of the female's copulation signal is accurately predictable. The morphology of Melittobia males is discussed in relation to this behaviour. Courtship of a related species, M.chalybii, is compared to the courtship of M.acasta.     

Complex display behaviour of Evarcha culicivora,an East African mosquito‐eating jumping spider

Abstract

Evarcha culicivora, an East African jumping spider (Salticidae), is an unusual predator because it feeds indirectly on vertebrate blood by choosing blood‐carrying mosquitoes as preferred prey. It also associates with particular plant species, Lantana camara and Ricinus communis. Here we document this species’ exceptionally complex display repertoire. In common with many other salticids, E. culicivora exhibits pronounced courtship versatility, with males using different tactics depending on the female's location and state of maturity. However, in contrast to most other salticids that have been studied, the males and the females of E. culicivora are both active at initiating and sustaining courtship, and both sexes are cannibalistic. Contrary to the emphasis in the literature on female spiders eating males, females of E. culicivora run a higher risk of being killed by males than vice versa during courtship. E. culicivora males also differ from other salticids that have been studied by adopting pronounced copulatory courtship. Male‐female interactions of E. culicivora are especially complex when encounters are in the foliage of L. camara and R. communis.     

COMPARATIVE ETHOLOGY OF THE CICONIIDAE. THE WOOD-STORKS (GENERA MYCTERIA AND IBIS)*

This paper reports on an 11-year study of the comparative behaviour of the four species of wood-storks. All species were studied under natural conditions at breeding colonies in the U.S.A., East Africa, India, and Indonesia. In addition, observations were made on hand-reared young of two species (Mycteria americana and Ibis ibis). Various aspects of signal (display) and non-signal behaviour are described. The most common ritualised display away from the nest is the Forward Threat. At the neBt, the following displays are seen, mainly during courtship and pair-formation: Aerial Clattering Threat, Forward Clattering Threat, Snap Display, Anxiety Stretch, Flying Around, Gaping, Balancing Posture, Swaying Twig-Grasping, Display Preening, Up-Down, and Copulation Clattering. Each of these patterns is described in the text and many of them are illustrated. The four species treated here are similar to each other in most behaviour patterns. They do show some quantitative differences in courtship displays, particularly in the Up-Down, a common “greeting” display shown to the mate at the nest. The behavioural and morphological evidence now available does not justify the separation of M. americana into a monotypic genus, and I suggest that all four wood-storks be combined in the genus Mycteria. Thus, the wood-storks include: M. americana, M. cinerea, M. ibis, and M. leucocephala.     

Laying date, clutch size and egg size of the Mallard Anas platyrhynchos and Tufted Duck Aythya fuligula

The effect of spring temperature on first egg date, laying period and last clutch date was studied in the Mallard and Tufted Duck. Seasonal clutch size and egg size trends were also examined. In years When Mallard laid early, Tufted Duck also did so. The first Mallard clutch was started earlier and laying period was longer in years with a high mean February temperature. The last clutch was started later in years with a high mean June temperature. In Tufted Duck the laying period increased and the last clutch was started later in years with high mean April temperatures.
Mean hatching date of Mallard clutches was later in years when the date of peak chironomid emergence was late.
In both species, clutch size declined through the season. Egg volume was not related to clutch size in either species, but egg volume in the Tufted Duck declined through the season. No difference in Tufted Duck egg size existed between sites, but the significance of egg size on duckling survival is discussed. Genetic factors related to individual consistency in egg size in Mallard may have obscured egg volume trends during the season because of renesting.     

Compared distribution within a disturbed fishpond ecosystem of breeding ducks and bird species indicators of habitat quality

The distribution of breeding ducks versus three other bird species (Mute Swan Cygnus olor, Black-headed Gull Larus ridibundus and Purple Heron Ardea purpurea) among waterbodies was investigated in the Dombes area, Eastern France, where breeding duck populations have undergone a severe decline following a large-scale transformation of meadow habitat into cropland. Higher Pochard Aythya ferina, Tufted Duck Aythya fuligula, Red-crested Pochard Netta rufina and Gadwall Anas strepera pair densities were recorded in fishponds where Black-headed Gulls were nesting. In these ponds however, nesting success (assessed by the number of broods divided by the number of pairs) was not significantly higher. Similarly, Pochard pair density was higher in ponds with a Purple Heron colony, but brood densities were not. We hypothesise that, in the study region, clutch concentration in the most attractive areas could compensate for the anti-predation effect of gull colonies or overwater nesting in shore vegetation. We could not confirm the expected negative impact of Mute Swan aggressive behaviour on duck distribution. Even though Mallard Anas platyrhynchos pair density was lower in ponds with breeding swans, we did not observe difference for Mallard broods. Moreover, Red-crested Pochard pair density and nesting success were higher in ponds where swans were breeding, probably as a consequence of shared habitat preferences.     

Sexual selection,reproductive behavior,and speciation in the mbuna species flock of Lake Malawi (Pisces: Cichlidae)

Synopsis The cichlid species flocks of the African Great Lakes represent the most extreme case of adaptive radiation among vertebrates. Recently, attention has focused on the potential for sexual selection to drive or accelerate speciation in these fishes. Cichlids as a whole are social in nature and display complex behavior, particularly during courtship and spawning; however, the extent to which changes in species recognition cues may account for species diversity among haplochromine lineages has remained speculative. Our investigations have indicated that oral incubating haplochromines show a reduction in diversity and extent of courtship relative to substrate brooding cichlids, and apparently retain aspects of a primitive specific mate recognition system. Laboratory observations of courtship in the Malawian endemicPseudotropheus zebra suggest that organization of the spawning bout is loose, and lacking in any well defined stimulus-response chain. Interspecific comparisons of in situ courtship behavior among male mbuna, lithophilous haplochromines of Lake Malawi, revealed only one potential example of species-specific behavior, and indicated that mate choice occurred prior to the onset of intense courtship. Courtship display by male mbuna does not appear critical to species recognition and may represent an evolutionary relict. Alternatively, male courtship display may have an indirect effect on successful reproduction or may be maintained through pleiotropic effects. The mbuna display no evidence of behavioral innovation and show limited interspecific differentiation in behavioral expression. More generally, there is no evidence at present to suggest that epigamic sexual selection, acting on courtship behavior, has been a major mechanism in the diversification of the haplochromine species flocks.     

The Influence of Sequential Male Courtship Behaviors on Courtship Success and Duration in a Terrestrial Salamander,Plethodon shermani

Most organisms use multiple cues across many modalities to assess potential mates. Salamanders in the genus Plethodon have an elaborate courtship display, yet previous studies primarily have concentrated on the influence of olfactory cues on courtship success. In this study, we tested whether two different cues (one chemical and one visual) affected courtship success and duration in the red‐legged salamander, Plethodon shermani. By staging and observing over 180 courtship trials, we found that ‘foot‐dancing’, a male visual cue performed in the earliest stages of courtship, significantly increased the likelihood that a male and female would progress to subsequent stages of courtship and, thus, the likelihood of insemination. In contrast, delivery of biologically relevant levels of a non‐volatile pheromone (produced in a large gland on the male's chin) during courtship trials did not increase overall insemination rate success, but did significantly reduce the duration of one of the later stages of courtship, tail‐straddling walk. Thus, we propose that early use of visual cues in Plethodon courtship, may (1) increase the detectability of the male message by increasing the range at which the male can be perceived by the female and (2) indicate the context of the male's approach and subsequent behaviors. In short, this study draws attention to the need to examine behavioral traits affecting courtship success at multiple stages and across several sensory modalities.     

Controlling the flood in the Senegal Delta: do waterfowl populations adapt to their new environment?

Triplet, P. & Yésou, P. 2000. Controlling the flood in the Senegal Delta: do waterfowl populations adapt to their new environment? Ostrich 71 (1 & 2): 106–111.

The delta of the Senegal river (320 000 ha) has been gradually dammed, mostly during the 1970–80s. From 1986, the Diama dam has stopped any backflow of salt water from the sea into most of the delta, and retains a large volume of fresh water which can be released into initially naturally flooded, but now embanked, areas, including the National Parks of Djoudj (Senegal) and Diawling (Mauritania) and other lowlands often used for agriculture, mainly rice-fields. Landscapes have been deeply modified (vegetation overgrowing in wetlands, desertification process around), sometimes in a provisionally positive way (creation or development of flooded areas through irrigation or hunting management). The Anatidae overwintering in the delta have been censused since 1972: we analyse these census data, with emphasis on the periods 1972–1976 and 1989–1996 (when census methodology and coverage were similar), in order to define how Anatidae have adapted to the new environmental conditions.

Three Afrotropical and two Palearctic species are holding on, in spite of marked yearly variations and sometimes a loss of habitat quality (Fulvous Whistling Duck Dendrocygna bicolor. White-faced Whistling Duck D. viduata, Egyptian Goose Alopochen aegyptiacus. Northern Pintail Anas acuta, Garganey A. querquedula), two Palearctic species showed significant but not fully explained changes in numbers (Northern Shoveler Anas clypeata increasing, Common Teal A. crecca almost disappearing), and numbers of two Afrotropical species decreased following the environmental modifications (Spur-winged Goose Plectropterus gambensis, and Comb Duck Sarkidiornis melanotos even more markedly).

In order to maintain or develop conditions favourable to these bird populations, it is necessary to supply the managers of protected areas with the resources needed to implement this aim. Also, the whole lower valley of the Senegal River (including the Lake of Aleg in Mauritania) must be taken into account in conservation measures, including non-protected areas potentially favourable to waterfowl. Such a conservation programme implies the co-operation of national and international bodies related to both nature conservation and wetland development.     

Patterns of inheritance of mating signals in interspecific hybrids between sailfin and shortfin mollies (Poeciliidae: Poecilia: Mollienesia)

Differences in male morphology and mating behaviors are thought to confer species sexual isolation between sailfin and shortfin species of mollies. This study used interspecific crosses between the sailfin molly, P. latipinna, and the shortfin molly, P. mexicana, to investigate patterns of inheritance of morphological traits and behavioral rates of three mating behaviors in F1 hybrid males. The two parental species showed clear species differences with respect to the length of the dorsal fin and dorsal fin ray number. First generation hybrid males were intermediate between the two parental species for dorsal fin length and fin ray number, suggesting autosomal control of this trait with little effect of dominance by genes from either parental species. Parental species showed clear species differences in their rates of courtship displays. Unlike the pattern for dorsal fin morphology, F1 hybrid males showed a clear distinction in display rates with respect to the direction of the interspecific cross. Male hybrids whose sires were P. latipinna had courtship display rates that were up to three times higher than the rates of displays performed by hybrid males whose fathers were P. mexicana. The distribution of phenotypes between the parental species and that of hybrid males sired by that parental species was nearly identical. Such a pattern suggests the influence of Y-linked genes on the inheritance of courtship display rates in mollies.     

Courtship Behavior of the Cumberland Plateau Woodland Salamander,Plethodon kentucki (Amphibia: Plethodontidae), with a Review of Courtship in the Genus Plethodon

Complete catalogs of courtship behavior are available for only seven of the 42 currently recognized species of Plethodon. Additional detailed studies of courtship behavior in Plethodon species are needed to analyze the evolution of courtship behavior in this genus. We investigated the courtship behavior of the Cumberland Plateau woodland salamander (Plethodon kentucki) and compared it to previous accounts of courtship in other Plethodon species. In the laboratory, we videotaped the complete courtship of 30 different P. kentucki pairs, which included 46 tail-straddling walks that resulted in spermatophore deposition. From a transition matrix of observed motor patterns, we constructed a flow diagram of significant motor-pattern transitions during courtship. In general, the courtship behavior of this species is very similar to that of other large eastern Plethodon; however, there are some notable differences. Prior to the tail-straddling walk, the male transfers courtship pheromone from his mental gland to the female's nasolabial grooves (via mental-gland tapping and ‘chin-to-chin’ behavior patterns) more frequently than in other Plethodon. In most courtships, the female initiates contact leading to the tail-straddling walk. Males exhibit a greater propensity to deposit multiple spermatophores per courtship (two deposited in 33% of courtships, three deposited in 10% of courtships, X = 1.53 spermatophores per courtship) than males of other plethodontids. Mean size of the spermatophore is smaller than in other large eastern Plethodon. Overall, the courtship behavior of this species is most similar to that of P. jordani.     

Conditional strategies and interpopulation variation in the behaviour of jumping spiders

Abstract

Conditional strategies and interpopulation variation in the mating and predatory behaviour of salticid spiders are reviewed. A functional approach is adopted, and defended, in which specified behavioural phenotypes are accounted for, in large part, by specified selection factors. Courtship versatility, in which a male's behaviour depends on the female's maturity and location, is common in the Salticidae. If a male encounters an adult female in the open, where there is ample ambient light, he performs vision-dependent displays (Type 1 courtship) in front of her. If he encounters an adult female inside her nest, he uses different displays (Type 2 courtship) which are not vision–dependent and consist of various tugging, probing and jerking movements on the silk of the nest. These displays apparently send vibratory stimuli to the female. When a male encounters a subadult female inside her nest, he initially performs Type 2 courtship, then spins a second chamber on the nest and cohabits until the female moults and matures. A modification of optimal foraging theory has been used to examine factors that influence interpopulation variation in male courtship persistence. A study of five populations corroborated predictions from the model. Persistence appears to be related to female availability. Female availability is related to local phenology, which is, in turn, related to local climate. Complex examples of predatory versatility also have evolved in the Salticidae, especially in the genus Portia. All species of Portia studied are araneophagic spiders that invade other spiders' webs and practise aggressive mimicry. Portia fimbriata, uniquely among Portia species studied, uses specialised behaviour to prey on other salticids. Portia fimbriata and one of the salticids on which it preys, Euryattus sp., appear to be co-adapted to each other.     

Observations of mixed-species bird flocks at Kichwa Tembo Camp,Kenya

Mixed-species foraging flocks were studied at Kichwa Tembo Camp on the edge of the Masai Mara National Reserve in Kenya between July and September 2004. Observations were made on 29 mixed-species flocks, in which 24 species participated. African Paradise-Flycatcher Terpsiphone viridis, Black-backed Puffback Dryoscopus cubla, Grey-backed Camaroptera Camaroptera brachyura, Collared Sunbird Hedydipna collars and Cabanis's Greenbul Phyllastrephus cabanisi were the most common participants in mixed-species flocks, as well as among the most frequently encountered bird species overall. The Black-backed Puffback was identified as the nuclear species in flocks due to their abundance and frequency with which they were followed by other species. Mixed-species flocks represent another niche dimension in this diverse bird community, but few of these species could be described as flock specialists; most of the birds observed in mixed-species flocks in this study were opportunistic attendant species, including the African Pygmy-Kingfisher Ispidina picta, not previously described as joining mixed-species flocks.     

Acoustic Component and Social Context of the Wing Display of the Walnut Fly Rhagoletis juglandis

Courtship signaling via wing vibration, accompanied by sound production, has been reported in several species of tephritids. In this large family of flies, sound communication as well as complex courtship displays appears to be restricted to species with lekking mating systems (i.e., Mediterranean fruit fly, Anastrepha and Dacus species). In contrast, in tephritid species with resource-defense mating systems, such as species in the genus Rhagoletis, little or no courtship behavior, acoustical or otherwise, has been described. Wing displays in Rhagoletis species have been considered to play a visual role. This study describes a distinctive wing display performed by males of the walnut fly, Rhagoletis juglandis. Laboratory experiments and field observations demonstrate that the male wing display plays a role in courtship. We used sound and vibration detectors to record the signals produced by this wing display. Using a combination of techniques, we were able to record both the very low-frequency vibration and its accompanying airborne infrasound (12–22 Hz) produced by the males.     

海南岛越冬水鸟资源状况调查

2003～2004年冬季,对海南岛沿海及其内陆湿地49个地点的越冬水鸟状况进行了全面调查,旨在为海南湿地的保护和管理提供科学依据。记录到越冬水鸟6目10科,共67种。发现了6种海南的新记录,分别为白琵鹭(Platalea leucorodia)、鸳鸯(Aix galericulata)、针尾鸭(Anas acuta)、绿头鸭(A．platyrhynchos)、红腰杓鹬(Numenius madagoscariensis)和流苏鹬(Philomachus pugnax)。