Rostrum Length Research Articles

Sex difference, growth pattern, and cephalic index of Turi ducks at different ages based on head morphometry

This study aims to determine the morphometric differences in the head of male and female Turi ducks. Ten male and ten female day-old ducks (DOD) were randomly selected by a lottery system from the population, raised, and had their head morphology measured using a digital caliper with an accuracy of 0.01 mm on the first day, and at the age of 2, 4, 6, and 8weeks. The result showed that male Turi duck had wider (p <0.05) head at the ages of 1 day, 2 and 6 weeks, head length and head height at the ages of 1 day, 2, 4, 6, and 8 weeks, rostrum width at the ages of 1 day, 4, 6, and 8 weeks, and rostrum length at the age of 2, 4, 6 and 8 weeks. There were no significant differences (p >0.05) in the head width at the ages of 4 and 8 weeks, rostrum width at 2 weeks, and rostrum length at 1day old male and female Turi ducks. Morphometric growth pattern showed that older Turi ducks (at a range of 1 day to 8 weeks) had larger (p <0.05) head morphometry. However, the cephalic index in male and female Turi ducks was not significantly different (p > 0.05) at all ages. It could be concluded that in general head morphometry was useful for determining male and female Turi ducks at the ages of 1 day, 2, 4, 6, and 8 weeks

Boll weevils in dry bolls: is there a performance disadvantage?

BackgroundAnthonomus grandis grandis is the main cotton pest in the Americas, with the potential to become a pest in other continents. The insect uses the plant’s reproductive organs for feeding, oviposition, and survival strategies in the off-season, sheltering in dry bolls. This study aimed to know the reproductive potential, feeding, longevity, and morphometric characteristics of boll weevils from dry bolls, squares, and traps. Adults were obtained from infested squares, dry bolls, and traps installed in cotton fields and the Caatinga area. Thirty weevil pairs were maintained in the laboratory to assess the oviposition, feeding holes, longevity, and morphometric measurements of the parental and F1 generations.ResultsIn the parental generation, boll weevils from traps (the Caatinga area and cotton cultivation) showed greater reproductive potential. Boll weevils from squares and the Caatinga area showed greater feeding activity compared with those from cotton cultivation. Greater rostrum length, thorax + abdomen length, and abdomen width were observed in boll weevils from cotton cultivation and dry bolls. The origin of boll weevils parental generation did not affect progeny emergence time. The F1 generation of boll weevils showed significant differences in average longevity depending on the origin of different microhabitats. Furthermore, differences in rostrum lengths were observed, with the boll weevils coming from traps installed in cotton cultivation, the Caatinga area, and dry bolls being the largest. Regarding thorax + abdomen length and abdomen width, the highest values were observed in those from the Caatinga area and cotton cultivation.ConclusionIt was proven that dry bolls did not affect the reproductive, feeding, and longevity performance of boll weevils, enabling better insect fitness (reproduction and size) in relation to those coming from squares. The use of dry bolls as off-season shelter is an important survival strategy for the boll weevil.

Morphological and Habitat of Parhippolyte uveae Borradaile 1900 from Tanjung Sanjangan Central Sulawesi

Parhippolyte uveae is a type of shrimp found in the Tanjung Sanjangan Tolitoli area, Central Sulawesi. The availability of red shrimp morphology and habitat data completes basic information, which is important in the sustainable management of the species. This research aims to describe the morphology and habitat of red shrimp from Tanjung Sanjangan, Tolitoli, Central Sulawesi. The sampling method uses a purposive sampling method with 5 sampling stations. The environmental parameters measured are temperature, salinity, pH, and substrate observations. The measurement results show temperatures ranging between 27.9°C -29.9°C, salinity 15-17 ppm, pH 6.29- 6.82 with coral, mud, and sand as a substrate. Morphometric data shows that the samples have a Total Length (PT) between 26-46.85 mm. Abdominal Length 18.3-30.4 mm, Carapace Length (PK) 7.5-13 mm, Carapace Width (LK) 5.25-9.5 mm, Rostrum Length (PR) 1.6-3.4 mm, Telson Length (PTel) 4.45-7.2 mm, First Abdominal Length (PabP) 1.4-2.15 mm and Second Abdominal Length (PabK) ranges from 1.8-4 mm. Meristic data shows that the Tanjung Sanjangan red shrimp has 3 upper rostrum teeth and 3-5 lower rostrum teeth, 3 pairs of dorsal spines, and 2 pairs of posterior spines. The results of these character observations are by the description of the P. uveae species.

Cranial variation between coastal and offshore bottlenose dolphins, Tursiops truncatus (Cetacea: Delphinidae) in Ecuador and the Mediterranean: a three-dimensional geometric morphometric study

Abstract Skull shape analysis provides useful information on wildlife ecology and potential local adaptations. Common bottlenose dolphins (Tursiops truncatus) often differentiate between coastal and offshore populations worldwide, and skull shape analyses can be particularly useful in this context. Here we quantify skull shape variation between coastal populations from the Gulf of Guayaquil (Ecuador) and the Mediterranean Sea, compared to offshore specimens from multiple oceans. We analysed skull shape differences using 3D models from museum specimens through geometric morphometrics (3DGM). Two complementary landmark approaches included single-point semi-landmarks in homologous features, as well as pseudo-landmarks placed automatically. Results show skull shape distinction between both coastal populations and offshore specimens. Offshore specimens showed little differentiation between distinct locations. Skull shape patterns mostly diverged in the shape and length of rostrum, as well as the shape of the ascending processes of the maxilla, pterygoids, and occipital bones. However, both coastal populations differed in the patterns and direction of change of those features and were also morphologically distinct. Our results are consistent with local data on site fidelity and social structure in the coastal populations. Skull shape changes suggest divergent feeding and sound production patterns are potential drivers, probably specific to the local environment of each community.

STUDI MORFOMETRIK UDANG BERAS MERAH (Metapenaeopsis palmensis) YANG TERTANGKAP PADA MALAM HARI DI PERAIRAN SAMBOJA KABUPATEN KUTAI KARTANEGARA

Southern Velvet Shrimp (Metapenaeopsis palmensis) of the Penaeidae family, morphometric measurements were carried out to see things that affect the shape of the species. This study was aimed to provide information about the morphometric study of red rice shrimp (Metapenaeopsis palmensis) caught at night in Samboja waters, Kutai Kartanegara. This research was conducted in October-November 2021, the sample used was 300 brown rice shrimp (Metapenaeopsis palmensis). The morphometric study used covariance analysis to look at 20 morphometric covariates that affect the total length (PTO). Based on the results of univariate anova test analysis, it is known that 20 morphometrics have a sig <0.05, which means that H1 is accepted, which means it has an effect on PTO. Furthermore, ancova analysis was carried out, 13 morphometric results were obtained which had sig <0.05 for PTO, namely rostrum length (RST), head length (PK), first segment length (PRP), second segment length (PRD), third segment length ( PRT), fourth segment length (PRE), fifth segment length (PRL), sixth segment length (PRN), headless length (PTK), telson length (TLN), carapace button length (PKB), third lower segment length (PTB) ), and the length of the fifth lower segment (PLB).

Geographic variation in external morphology of North Pacific and Southern Hemisphere blue whales (Balaenoptera musculus)

Geographic variations in size and proportions of blue whales (Balaenoptera musculus) were investigated using length data acquired from whaling records and aerial photogrammetric surveys. Results showed that blue whales found in the eastern Pacific off Central and North America are significantly shorter (by approximately 2m) than blue whales found at higher latitudes in the North Pacific. Results support the occurrence of a morphologically distinct eastern North Pacific (ENP) blue whale population which migrates in spring/summer from warm waters off Central America and Mexico to temperate feeding grounds along the west coast of North America. Southern Hemisphere blue whales sampled with vertical aerial photogrammetry off northern Peru and the Galapagos Islands were similar in size to the ENP blue whales. However, the population affinity of these southern blue whales remains uncertain. No length data were available for blue whales formerly captured off southern Japan and Korea. Nonetheless, a history of diminishing fishery catches and a lack of any recent sightings suggests that these whales were members of a geographic population that is now severely depleted or extinct. Based on comparisons of total length, length of rostrum and length of tail region, ENP blue whales were found to be morphologically similar to the ‘pygmy’ blue whale (B.m. brevicauda) described from the Kerguelen Island region of the southern Indian Ocean. ‘Antarctic’ blue whales (B.m. intermedia) from the Southern Ocean were found to be statistically significantly larger than their conspecifics at high latitudes in the North Pacific. These results support the hypotheses that blue whales that migrate from warm seas to cold feeding grounds in high latitudes are larger than those whose distributions are limited to low and mid-latitudes. Differences in morphology may reflect selective pressure on populations to adapt physiologically to energy demands associated with different migration, environmental and ecological regimes. As some of the results come from populations located far apart in different oceans, questions remain concerning the continuity of populations within and among ocean basins. Consequently, research using fishery data and approaches such as photogrammetry, telemetry, acoustics and molecular genetic analysis should be continued to better understand the worldwide blue whale population structure.

A contribution on the morphometrics of the thick-clawed crayfish Pontastacus pachypus (Rathke, 1837) (Decapoda, Astacoidea, Astacidae)

The thick–clawed crayfish Pontastacus pachypus (Rathke, 1837) is an endangered, and the least known, crayfish species in Europe. Currently, detailed information regarding the morphology, ecology and reproduction of thick–clawed crayfish is outdated. This study presents, for the first time, detailed photographs of the thick-clawed crayfish, and updated information on distinctive morphological characters and morphometric analysis. New specifications of the carapace and appendage morphological characteristics were established as: 1) the rostrum is long, sharply pointed and has three pairs of distinctive sub-apical lateral spines, 2) two well–developed pairs of post–orbital ridge on the carapace are ended by prominent spine; 3) each finger of chelae ends with a black sharp tip. Among the 18 morphometric indices, carapace width to the total length (CPW/TL), abdomen width to the total length (ABW/TL) and claw height to the claw width (CLH/CLW) clearly differentiate P. pachypus from the other representatives of Astacus genus (A. colchicus and A. astacus) and P. leptodactylus (P<0.05). Comparison of individual indices between P. pachypus and P. leptodactylus revealed that almost all indices differed significantly except head length to the total length (HEL/TL) and rostrum length to the total length (ROL/TL). This study contributes to the identification of the thick–clawed crayfish for the purpose of conservation and protection of its localities.

Ecological conditions and phenotypic characteristics of Austropotamobius torrentium (Schrank, 1803) in the Subotica and Toplik Rivers

Austropotamobius torrentium (Schrank, 1803) lives in two watercourses, namely Subotica (Sana) and Toplik (Tilava). The influence of the ecological conditions of these rivers on individuals of this species is analyzed based on 22 morphometric parameters. The assessment of abiotic conditions was done through the measurement of physical and chemical water parameters and the analysis of the composition of phytobenthos and macrozoobenthos. Sampling was carried out in June, September, and October 2021. Water quality at the investigated localities (on the basis of abiotic and biotic parameters) is oligo to betamesosaprobic. A total of 37 crayfish were analyzed (20 from Subotica and 17 from Toplik). Female crayfish have shown significant differences in the head width (HEW) and abdominal thickness (ABH). Males differed significantly in a number of parameters, including the weight (W), head shape (HEL and HEW), rostrum length (ROL), carapace width (CPW), and abdominal shape (ABH and ABL). Higher values of the indicated parameters have been found in the males from the Subotica River. The obtained results are influenced by different ecological conditions of their habitats. The Subotica River is a larger watercourse in the lowland belt with a large number of microhabitats, and the Toplik is a small river in the mountain belt, with uniform sediment and a small number of ecological niches of the analyzed species. The general ecological conditions in the water of both watercourses are also affected by aquaculture facilities, where wastewater has a direct influence on the distribution of Austropotamobius torrentium individuals in the watercourses of the Subotica and Toplik Rivers. For more detailed and complete data, it is necessary to analyze a larger number of individuals in both populations, and to include additional morphometric-meristic parameters and molecular-genetic analyses.

Morphological discrimination of tiger shrimp Penaeus monodon between female and male based on traditional and truss morphometric analyses

The morphological difference of tiger shrimp, Penaeus monodon from Aceh waters is limited to explore for female and male discrimination using morphometric analyses. The study aimed to evaluate the morphological characters between female and male tiger shrimp using traditional and truss measurements. A total of 57 samples (39 females and 18 males) were analysed using 9 characters for traditional morphometric and 40 characters for truss morphometric. Multivariate analyses were applied to reveal the morphometric variation between male and female populations. The result of principal component analysis indicated that 4 characters, i.e: carapace length (CL), carapace width (CW), rostrum length (RL), and sixth segment length (SL6), were significantly different (P<0.05), while three truss morphological characters, i.e: distance between anterior and posterior carapace, distance between ventral posterior sixth segment to telson end, and distance between anterior and posterior second segment, were significantly discriminated (P<0.05) between female and male of tiger shrimp. Overall, 94.9% of the male and 88.9% of the female individuals were assigned to their native populations using traditional morphometric analysis, while truss morphometric was 87.2% and 88.9%, respectively. The individual proportion of 93.0% was properly classified into their original population group for traditional morphometric and 87.7% for truss morphometric characters.

Local Agricultural Management Filters Morphological Traits of the South American Palm Weevil (Rhynchophorus palmarum L.; Coleoptera: Curculionidae) in Ornamental Palm Plantations

Insect pests show phenotypic plasticity as a function of resource availability and limiting conditions. Although Rhynchophorus palmarum displays high variation in certain morphological traits, it is still not clear how and which of these are being filtered along agricultural management gradients in palm plantations. This study assesses the influence of biophysical structure of ornamental palm plantations and agrochemical use on morphological traits of adults in 15 permanent plots of ornamental palm plantations in Veracruz, Mexico. A total of 4972 adults were and their body length, pronotum width, rostrum length, and mesothorax depth were measured. Body length and mesothorax depth of adults of both sexes were greater in plantations with a high diversity of palm species and frequency of fertilizer use. Rostrum length of females increased as a function of palm density, and pronotum width of both sexes was positively related with the use of insecticides. Local characteristics of agricultural management of palm plantations might filter integrated, adaptative, and environment-specific phenotypes. This is the first ecological study of the south American palm weevil that provides new insights on the current intensive management of ornamental palm plantations that far from controlling, benefits current geographic expansion, demographic outbreak, and economic impact of this pest.

The morphological allometry of four closely related and coexisting insect species reveals adaptation to the mean and variability of the resource size.

The size of organisms may result from various, sometimes antagonistic forces operating on distinct traits, within an evolutionary framework that may also be constraining. Morphological allometry, referring to the way trait size scales with body size, has been shown to reflect ecological adaptation to the mean size of the resource exploited. We examined the allometric relationships between rostrum and body size among four insect (Curculio spp.) specialists of oak acorns. In all four species, weevil females drill a hole with their rostrum prior depositing one or a few eggs inside the seed. The four weevil species, that coexist on the same individual trees, displayed partitioned egg-laying periods in the year, thereby encountering acorns of different size and maturation stage. We found marked differences in the allometric slope among females: species laying eggs late in the season had a steeper slope, leading to increasingly longer rostrum relative to body length, along with the mean size of the growing acorns. Females of the smallest species had the longest oviposition period and also had the steepest slope, which provided them with the most variable rostrum length, thereby matching the variable size of the resource through time. Our work highlights the need to consider not only the average size but also the degree of variability in resource size to understand the adaptive value of allometric relationships.

Cranium morphometry for distinguishing male and female Muscovy duck (Cairina moschata) before sexual maturity

Gender determination of Muscovy duck as early as possible is essential for the efficiency and effectiveness of duck production. This study aimed to determine the morphometric differences in prepubertal male and female Muscovy duck (Cairina moschata) as predictors of gender. This study used a split-plot design, with the observed variables cranium length, width and height, mandibular length, and rostrum length and width. This study used a total of 80 samples of duck heads consisting of 40 male and 40 female Muscovy duck heads, with ten heads each in the age group of 2, 4, 6, and 8 weeks, respectively. Results showed that the length, width, and height of the cranium, mandibular length, and rostrum lengthand width were greater in males (p &lt;0.05) than those of the females in all age groups. It could be concluded that the morphometric size of prepubertal male Muscovy ducks head was greater than those of the female ones at the same age; thereby, it could be used to distinguish gender. Based on the morphometrics, further study can also be conducted to measure other body parts of the Muscovy duck apart from the cranium. In addition, it is necessary to study the morphometric measurements of the cranium in other poultry as a basis for identifying sex.

Beak Microstructure Estimates of the Age, Growth, and Population Structure of Purpleback Flying Squid (Sthenoteuthis oualaniensis) in the Xisha Islands Waters of the South China Sea

This study aimed to explore the feasibility of using an upper beak microstructure to estimate the age of purpleback flying squid (Sthenoteuthis oualaniensis). From these microstructures, the age and growth of squid caught from January to March and May to August in 2018, 2019, and 2020 in the waters surrounding the Xisha Islands in the South China Sea were determined. We found three typical growth zones (the hood region, crest region, and axis), abnormal increments (checks), and erosion in the beak examination. The average dorsal mantle length (ML) of males and females was 112.13 (±15.23 mm) and 119.67 mm (±24.50 mm), respectively, and no squid were older than 10 months. The peak hatching dates, according to back calculations, were from October to January of the next year. All sampled squid belonged to the autumn/winter cohort. Significant sex differences were found in the relationship between ML and age in squid with similar growth patterns. Exponential models best described the relationships of ML with age and body weight (BW) for both sexes. However, a linear model best described the relationship between age and upper rostrum length (URL). The maximum absolute daily growth rates (AGR) of BW were reached during days 240–270 for both sexes. The maximum AGRs in ML were reached during days 180–210 and 240–270 for males and females, respectively. The period of 120–150 days (4–5 months) was considered the sub-adult stage of S. oualaniensis in the Xisha Islands waters of the South China Sea. This study confirmed that the beak microstructure provides good age estimates for purpleback flying squid (S. oualaniensis).

European Lobster Larval Development and Fitness Under a Temperature Gradient and Ocean Acidification.

Climate change combined with anthropogenic stressors (e.g. overfishing, habitat destruction) may have particularly strong effects on threatened populations of coastal invertebrates. The collapse of the population of European lobster (Homarus gammarus) around Helgoland constitutes a good example and prompted a large-scale restocking program. The question arises if recruitment of remaining natural individuals and program-released specimens could be stunted by ongoing climate change. We examined the joint effect of ocean warming and acidification on survival, development, morphology, energy metabolism and enzymatic antioxidant activity of the larval stages of the European lobster. Larvae from four independent hatches were reared from stage I to III under a gradient of 10 seawater temperatures (13–24°C) combined with moderate (∼470 µatm) and elevated (∼1160 µatm) seawater pCO2 treatments. Those treatments correspond to the shared socio-economic pathways (SSP), SSP1-2.6 and SSP5-8.5 (i.e. the low and the very high greenhouse gas emissions respectively) projected for 2100 by the Intergovernmental Panel on Climate Change. Larvae under the elevated pCO2 treatment had not only lower survival rates, but also significantly smaller rostrum length. However, temperature was the main driver of energy demands with increased oxygen consumption rates and elemental C:N ratio towards warmer temperatures, with a reducing effect on development time. Using this large temperature gradient, we provide a more precise insight on the aerobic thermal window trade-offs of lobster larvae and whether exposure to the worst hypercapnia scenario may narrow it. This may have repercussions on the recruitment of the remaining natural and program-released specimens and thus, in the enhancement success of future lobster stocks.

Challenging ecogeographical rules: Phenotypic variation in the Mountain Treeshrew (Tupaia montana) along tropical elevational gradients.

Bergmann’s and Allen’s rules were defined to describe macroecological patterns across latitudinal gradients. Bergmann observed a positive association between body size and latitude for endothermic species while Allen described shorter appendages as latitude increases. Almost two centuries later, there is still ongoing discussion about these patterns. Temperature, the common variable in these two rules, varies predictably across both latitude and elevation. Although these rules have been assessed extensively in mammals across latitude, particularly in regions with strong seasonality, studies on tropical montane mammals are scarce. We here test for these patterns and assess the variation of several other locomotory, diet-associated, body condition, and thermoregulatory traits across elevation in the Mountain Treeshrew (Tupaia montana) on tropical mountains in Borneo. Based on morphological measurements from both the field and scientific collections, we found a complex pattern: Bergmann’s rule was not supported in our tropical mountain system, since skull length, body size, and weight decreased from the lowest elevations (<1000 m) to middle elevations (2000–2500 m), and then increased from middle elevations to highest elevations. Allen’s rule was supported for relative tail length, which decreased with elevation, but not for ear and hindfoot length, with the former remaining constant and the latter increasing with elevation. This evidence together with changes in presumed diet-related traits (rostrum length, zygomatic breadth and upper tooth row length) along elevation suggest that selective pressures other than temperature, are playing a more important role shaping the morphological variation across the distribution of the Mountain Treeshrew. Diet, food acquisition, predation pressure, and/or intra- and inter-specific competition, are some of the potential factors driving the phenotypic variation of this study system. The lack of variation in body condition might suggest local adaptation of this species across its elevational range, perhaps due to generalist foraging strategies. Finally, a highly significant temporal effect was detected in several traits but not in others, representing the first phenotypic variation temporal trends described on treeshrews.

Morphometric characteristics and condition indices of stone crayfish Austropotamobius torrentium (Shrank, 1803) from the Mlinska River

Regarded as a protected species on the IUCN list of endangered species, and classified as data deficient species, the stone crayfish (Austropotamobius torrentium) is one of the five European species from the Astacidae family that lives in freshwater ecosystems across Bosnia and Herzegovina. The aim of this study was to investigate the variability of selected morphometric characteristics of male and female crayfish of the A. torrentium species from the upper reaches of the Mlinska River. The crayfish were sampled in June 2021 when 62 individuals (22 males and 40 females) were caught. They were analyzed fresh in the field and in the laboratory. The treatment included the measurement of 12 morphometric features: total body length (TBL), weight (W), claw length (CLL), claw width (CLW), carapace length (CPL), carapace width (CPW), rostrum length (ROL), rostrum width (ROW), abdominal length and width (ABL, ABW) and telson length and width (TEL, TEW). The mean body length ± SD was 79.05 ± 7.35 in males and 60.54 ± 10.03 mm in females. The mean recorded body weight ± SD was 17.51 ± 8.3 g in males and 7.02 ± 4.41 g in females. Using the linear regression method, a positive correlation was found between body length and weight (♂ R2=0.7644; ♀ R2=0.8222), body weight and claws length (♂ R2=0.876; ♀ R2=0.9661), as well as carapace width and body length (♂ R2=0.7216; ♀ R2=0.8411). Using the T-test, a statistically significant difference of the analyzed morphometric parameters was found between the sexes, which is explained by the pronounced sexual dimorphism of stone crayfish. The calculated values for Condition factor and the Crayfish constant indicate that the males are of better fitness, which is in line with the results of previous research in Europe. Data presented in this paper can serve as a basis for further research of A. torrentium in this area.

Ultrastructure Traits and Genetic Variability of Red Palm Weevil Rhynchophorus ferrugineus (Olivier) Adults from Different Geographical Locations in Egypt

The Red Palm Weevil (RPW) is one of the most damaging pests to palm cultivation; this invasive weevil poses a threat to the palm industry. The characterization and identification of this pest in order to determine its biological diversity is the first step in controlling it, which will help in developing effective control programs. The purpose of this study is to investigate the biodiversity of and characterize RPW from five different Egyptian geographical locations at morphological and genetic levels using morphometric analysis, scanning electronic microscopy and two different genetic markers. Our results revealed no significant differences between length and width of the adult body among RPW adults from different geographical locations. Different typologies of prothoracic spots were observed, indicating a degree of diversity in the RPW populations. The magnitude of the different body parts was measured among both males and females. Significant differences were exhibited between length of the antennal seta, as well as forelegs, the lengths and widths of the pronotum, and the rostrum length between both sexes. Both RAPD and ISSR used DNA markers, generating reproducible and distinct banding patterns. The polymorphic banding patterns that have resulted from all studied populations confirmed that these markers demonstrate genetic variability amongst the studied Egyptian populations of Rhynchophorus ferrugineus. The recorded differences may be due to the presence of different red palm weevil genotypes. The obtained results might have potential applications in developing a new tracking and control strategy for this invasive pest.

Two new species of Macrobrachium Spence Bate (Decapoda: Palaemonidae) from Ayeyarwady River, Myanmar with a note on Macrobrachium lamarrei (H. Milne Edwards 1837)

Two new species of the genus Macrobrachium Spence Bate have been described from near Mandalay of Ayeyarwady (Irrawaddy) River, Myanmar (22°2′37″N; 96°2′37″E). Macrobrachium univmandalay sp. nov. is closely related to Macrobrachium spinosum Cai & Ng, 2002 and Macrobrachium yui Holthuis, 1950 and is characterized by the presence of 10–12 dorsal teeth of which 3–4 post-orbital, first tooth at about 1/4th of anterior carapace; second chelate legs are dissimilar in size and shape in which carpus of major leg distinctly shorter than palm, cutting edges of fingers with 2 large and 2–3 smaller denticles at proximal part and without denticles on the distal half. Minor leg in which merus longer than carpus and palm, carpus shorter than palm as well as fingers and fingers without denticles in the cutting edges. M. spinosum and M. yui differ from this species in all these characters above.Macrobrachium ayeyarwadiense sp. nov. shows close affinity with Macrobrachium horstii de Man, 1892 and M. spinosum and can be easily separated on the basis of difference in characters of rostrum, position and arrangement of teeth on upper and lower margins, position of first dorsal tooth, distance between post-orbital edge and first dorsal tooth and its relation to rostrum length, length of antennular peduncle in relation to post-orbital carapace, shape and structure of 2nd cheliped, nature, size and arrangement of spines on outer and inner margins of ischium, merus, carpus, palm and fingers and nature of denticles on cutting edges of major and minor legs. The species can at once be identified on the absence of tubercles at distal half beyond larger denticles on fingers, convex nature of merus, carpus and disposition of spines on them, swollen palm and curved nature of movable finger and crossed nature of fingers distally of major 2nd peraeopod. Nature of long stiff setae on inner side of ischium, merus and carpus of major cheliped is characteristic to the species. Minor 2nd cheliped is also species specific in which the fingers are slender and curved so that a wide gap exists when closed. A note on Macrobrachium lamarrei (H. Milne Edwards 1937) is also given in the text.

Geographic variation in shoot structure in association with fruit size in an evergreen woody species.

The generality of scaling relationships between multiple shoot traits, known as Corner’s rules, has been considered to reflect the biomechanical limits to trees and tree organs among the species of different leaf sizes. Variation in fruit size within species would also be expected to affect shoot structure by changing the mechanical and hydraulic stresses caused by the mass and water requirement of fruits. We investigated the differences in shoot structure and their relationship with fruit size in Camellia japonica from 12 sites in a wide geographic range in Japan. This species is known to produce larger fruits with thicker pericarps in more southern populations because warmer climates induce more intensive arms race between the fruit size and the rostrum length of its obligate seed predator. We found that, in association with the change in fruit size, the diameter and mass of 1-year-old stems were negatively associated with latitude, but the total mass and area of 1-year-old leaves did not change with latitude. Consequently, the length of 1-year-old stems and the total mass and area of 1-year-old leaves at a given stem diameter were positively associated with latitude in the allometric relationships. In contrast, the allometric relationships between stem diameter and total mass of the 1-year-old shoot complex (the leaves, stems and fruits that were supported by a 1-year-old stem) did not differ across the trees of different latitudes. Thus, natural selection on fruit size is considered to influence the other traits of Corner’s rules in C. japonica, but all of the traits of Corner’s rules do not necessarily change in a similar manner across latitudinal gradients.

Gender Identification of Sitophilus oryzae using Discriminant Analysis and Support Vector Machine: A comparison study

Sitophilus oryzae (rice weevil) known as severe pest to many stored products, including rice. Gender density of S. oryzae is a critical information in predicting the rate of stored grain lost. However, the techniques used in gender identification of S. oryzae is a destructive technique which involved dissection to identify its reproductive organ. It was a tidious work and very time consuming. Thus, this study focused on the use of non destructive technique which only based on numerical information of S. oryzae morphological features to identify its gender. The numerical information was analysed and tested against two model i.e. Discriminant Analysis Model and Support Vector Machine Model. The result show that rostrum length and width were adequate to be used in the Discriminant Analysis Model for gender identification of S. oryzae with 91% correct classification, while Support Vector Machine Model perform poorly in classification with 62% correct classification. Gender identification of S. oryzae using numerical information features were more accurate and liable compared to normal identification which based on the internal reproductive organ.