The role of boundary length and adjacent patch contrast in guppy mate choice

The presence of various combinations of adjacent colors within polymorphic species’ color pattern could have a major impact on mate choice. We studied the role of pattern geometry in predicting mate choice in guppies using boundary strength analysis (BSA). BSA estimates the visual contrast intensity between two adjacent color patches (ΔS) weighted by the lengths of the boundaries between these adjacent color patches. We measured both the chromatic (hue and saturation) and achromatic (luminance) ΔS for each pair of adjacent patches. For each male’s color pattern, we measured BSA as both mean (mΔS) and coefficient of variation (cvΔS) of all ΔS weighted by their corresponding boundary lengths. We also determined if specific color patch boundaries had an impact on female preferences and whether these predicted overall male contrast (mΔS). We found that males with a higher mΔS were more attractive to females and that six boundaries containing either fuzzy black or black as one of the pair colors significantly affected female preferences, indicating that 1) females favored highly conspicuous males and 2) melanin-based patches could be used as a signal amplifier, not only for orange but for other colors.

A new species of Pupulina van Beneden, 1892 (Copepoda, Siphonostomatoida, Caligidae) from Aetobatus cf. narinari (Pisces, Myliobatidae) from the Pacific coast of Ecuador

A new caligid copepod species, Pupulinamantensissp. n. is described based on female and male specimens collected from the gills of the myliobatid elasmobranch Aetobatuscf.narinari Euphrasen, 1790 captured off the Pacific coast of Ecuador. The new species has a unique combination of characters that diverges from its known congeners, including: (i) weakly developed posterolateral processes on the genital complex; (ii) large spines on posterior surface of maxilliped basis (iii) abdomen slender, unsegmented, approximately 1/2 length and 1/5 width of genital complex; (iv) third exopodal segment of leg II with single long naked spine adjacent to minute, naked lateral spine; (v) velum of leg II with adjacent patch of denticles; (vi) caudal rami slightly less than half the length of genital complex; (vii) post-antennal process with robust, posteriorly directed tine, sclerotized stump posterolaterally, and two multi-sensillate papillae located on or near base of process (viii) post-oral process oval. The overall prevalence of P.mantensissp. n. on its host was 37.5% and its mean abundance was 1.87 specimens per host. This is the second record of the genus Pupulina from Ecuador and the second record of Pupulina infecting rays of the Myliobatinae genus Aetobatus, of the subfamily Myliobatinae, after its discovery on A.ocellatus in Australia, thus confirming this expansion of its previously known host range to a new elasmobranch subfamily.

Species presence frequency and diversity in different patch types along an altitudinal gradient:Larix chinensisBeissn in Qinling Mountains (China)

Forest communities are mosaic systems composed of patches classified into four different developmental patch types: gap patch (G), building patch (B), mature patch (M) and degenerate patch (D). To study the mechanisms maintaining diversity in subalpine coniferous forests, species presence frequency and diversity in the four distinct patch types (G, B, M and D) ofLarix chinensisconifer forests at three altitudinal gradients in the Qinling Mountains were analyzed. Our results were as follows: (1) Different species (or functional groups) had distinct presence frequencie s in the four different patch types along the altitudinal gradient; (2) Some species or functional groups (species groups sharing similar traits and response to environment) only occurred in some specific patches. For seed dispersal, species using wind mainly occurred in G and D, while species using small animals mainly occurred in B and M; (3) Species composition of adjacent patch types was more similar than non-adjacent patch types, based on the lowerβdiversity index of the former; (4) The maximum numbers of species and two diversity indices (D′ andH′) were found in the middle altitudes. Various gap-forming processes and dispersal limitation may be the two major mechanisms determining species diversity inLarix chinensisconiferous forests at the patch scale.

Species presence frequency and diversity in different patch types along an altitudinal gradient: Larix chinensis Beissn in Qinling Mountains (China)

Forest communities are mosaic systems composed of patches classified into four different developmental patch types: gap patch (G), building patch (B), mature patch (M) and degenerate patch (D). To study the mechanisms maintaining diversity in subalpine coniferous forests, species presence frequency and diversity in the four distinct patch types (G, B, M and D) of Larix chinensis conifer forests at three altitudinal gradients in the Qinling Mountains were analyzed. Our results were as follows: (1) Different species (or functional groups) had distinct presence frequencie s in the four different patch types along the altitudinal gradient. (2) Some species or functional groups (species groups sharing similar traits and response to environment) only occurred in some specific patches. For seed dispersal, species using wind mainly occurred in G and D, while species using small animals mainly occurred in B and M. (3) Species composition of adjacent patch types was more similar than non-adjacent patch types, based on the lower β diversity index of the former. (4) The maximum numbers of species and two diversity indices (D′ and H′) were found in the middle altitudes. Various gap-forming processes and dispersal limitation may be the two major mechanisms determining species diversity in Larix chinensis coniferous forests at the patch scale.

Species presence frequency and diversity in different patch types along an altitudinal gradient: Larix chinensis Beissn in Qinling Mountains (China)

Forest communities are mosaic systems composed of patches classified into four different developmental patch types: gap patch (G), building patch (B), mature patch (M) and degenerate patch (D). To study the mechanisms maintaining diversity in subalpine coniferous forests, species presence frequency and diversity in the four distinct patch types (G, B, M and D) of Larix chinensis conifer forests at three altitudinal gradients in the Qinling Mountains were analyzed. Our results were as follows: (1) Different species (or functional groups) had distinct presence frequencie s in the four different patch types along the altitudinal gradient. (2) Some species or functional groups (species groups sharing similar traits and response to environment) only occurred in some specific patches. For seed dispersal, species using wind mainly occurred in G and D, while species using small animals mainly occurred in B and M. (3) Species composition of adjacent patch types was more similar than non-adjacent patch types, based on the lower β diversity index of the former. (4) The maximum numbers of species and two diversity indices (D′ and H′) were found in the middle altitudes. Various gap-forming processes and dispersal limitation may be the two major mechanisms determining species diversity in Larix chinensis coniferous forests at the patch scale.

Design and Research on a 24GHz Microstrip Array Antenna

A 24 GHz microstrip array antenna based on series and parallel combination feeding network is designed in this paper by theoretical and experimental study. The whole design process includes theoretical analysis, HFSS ( High Frequency Structure Simulator ) simulation and practical manufacture. The array antenna design mainly includes four parts, design of the microstrip patch element, determining the number of radiating patch elements, determining the distance between every two adjacent patch elements and design of feeding network. Then, the microstrip array antenna is simulated and optimized by HFSS. The simulation results show that the VSWR ( Voltage Standing Wave Ratio ) characteristics present good, the maximum gain reaches 21dB and E-plane together with H-plane half-power beamwidth is as small as about 11.8 o . Both of the first side lobe levels are about-14 dB reaching the design requirements. After practical manufacture, the testing results show that the various indicators coincide with the simulation results and the antenna is reliable with stable performance.

Movement and size stucture in a poulation of the blue starfish Linckia laevigata (L.) at Lizard Island, Great Barrier Reef

On a patch reef surrounded by sand, the movements of L. laevigata conformed to Underwood's random walkmodel in most respects except that animals navigated unidirectional paths across the reef. At the edge of the reef, animals either turned back onto the reef or moved away across the sand, and this behaviour was studied in translocation experiments. When released on sand, L. laevigata navigated randomly distributed unidirectional paths. at speeds 10-20 times faster than on the reef. In this way, animals could migrate between patch reefs inhabited by L. laevigata of different sizes. Larger animals usually lived in deep water (≥ 10 m), but significant size differences were also found between adjacent patch reefs and were tentatively ascribed to variations in availability of food. Mean arm length of 26 animals starved in an aquarium for 1 week decreased from 115.4 to 108.5 mm, indicating that body size may change when L. laevigata migrates between patch reefs.