The anatomy of the fruit in relation to the propensity of citrus species to split

The anatomy of the fruit has been compared in three prone-to-split mandarin hybrids (Nova, Ellendale and Murcott), several cultivars of clementine mandarin (Fino, Clementina de Nules and Orogrande), and in Owari satsuma mandarin. The fruit of the hybrids is oblate to subglobose and usually presents an open stylar end disrupted by a navel formed by the floral meristem, which is conserved near the apex of the fruit. In the non-prone-to-split clementines as well as in Owari satsuma, the floral axis protrudes inside the style, and the flower meristem is lost through abscission shortly after petal fall. The abaxial side of the carpels fuses with the flower axis forming at the stylar end of the fruit a solid tissue which externally has a small scar at the place of style abscission. Most of the fruits in these cultivars have no navel. In addition, the fruit of clementine is slightly oblate or globose. The relevance of these anatomical characteristics as regards to splitting is supported by the differences between the split and non-split fruits in Nova, the split fruit being more oblate in shape and having a bigger navel than non-split fruit. However, the effect of applied growth regulators on fruit splitting could not be correlated with their effect on the anatomy of the fruit. Additional factors not contemplated in the study also influence fruit splitting

Características morfométricas de Talitroides topitotum (Burt) (Crustacea, Amphipoda, Talitridae) na Serra do Mar, Guaratuba, Paraná, Brasil Morphometric characteristics of Talitroides topitotum (Burt) (Crustacea, Amphipoda, Talitridae) from Serra do Mar, Guaratuba, Paraná, Brazil

Um estudo sobre as relações morfométricas entre o comprimento cefálico (Lc) e o comprimento total do corpo (Lt), e o número de artículos do flagelo do primeiro e segundo pares de antenas e o comprimento total do corpo foi realizado em uma população de Talitroides topitotum (Burt, 1934), no entorno da Usina Hidroelétrica de Guaricana, Guaratuba, Paraná. O objetivo foi auxiliar na inferência do comprimento do corpo a partir do comprimento cefálico e da idade relativa dos exemplares pela contagem do número de artículos de seus flagelos antenais. Um total de 975 exemplares foi coletado e fotografado, dos quais os artículos dos flagelos direito e esquerdo das antenas 1 e 2 foram contados e os comprimentos do segmento cefálico e do corpo foram medidos. Houve uma correlação linear entre o comprimento do segmento cefálico e o comprimento total do corpo definido pela equação Lc = 0,0506Lt + 0,3297; r² = 0,9577. Diferenças significativas foram observadas entre os números de artículos dos flagelos direito e esquerdo de ambas as antenas. A diferença foi de até quatro artículos no primeiro par de antenas e de doze no segundo. O maior número de artículos entre os dois flagelos mostrou uma correlação com a distribuição das classes de comprimento total do corpo com a equação a1 = 4,3463Lt0,4264 para o primeiro par de antenas, e a2 = 10,5700Lt0,3581 para o segundo par. Foi possível inferir o estágio relativo de desenvolvimento de T. topitotum pelas medidas do comprimento do segmento cefálico. Entretanto, somente o maior número de artículos entre os flagelos direito e esquerdo constitui parâmetro de referência para inferir a idade relativa dos indivíduos desta espécie.<br>A research on the relationship between the cephalic segment length (Lc) and total body length (Lt), and between the number of articles in the antenna flagellum and the total body length was conducted in a population of the terrestrial amphipod Talitroides topitotum (Burt, 1934) from Serra do Mar, Guaratuba, Paraná. It aimed to help the inference of the body length by measuring only the cephalic segment, and to know the relative age of individuals by counting the number of articles in their antenna flagellum. A total of 975 amphipods were caught with Malaise nets; they were photographed, the article number of the flagellum of the right and left antennae 1 and 2 was counted and cephalic segment length and their total body length was taken. There was a linear correlation between cephalic segment length and total body length defined through the equation Lc = 0.0506Lt + 0.3297; r² = 0.9577. There was a significant difference in the article number between the right and left flagellum, for both pairs of antennae. The difference was at most four articles for the fist antenna pair and twelve articles for the second one. The highest number of these articles between right and left flagellum showed a linear correlation with the total body length classes and it was expressed by the equation a1 = 4.3463Lt0.4264 for the first pair of antenna, and a2 = 10.5700Lt0.3581 for the second pair. I was possible to infer the relative stage of development of T. topitotum by measuring the cephalic segment length. However, only the highest number of articles between right and left flagellum constitutes a reference parameter for the inference of individual relative age in this species

Global collision-risk hotspots of marine traffic and the world’s largest fish, the whale shark

Marine traffic is increasing globally yet collisions with endangered megafauna such as whales, sea turtles, and planktivorous sharks go largely undetected or unreported. Collisions leading to mortality can have population-level consequences for endangered species. Hence, identifying simultaneous space use of megafauna and shipping throughout ranges may reveal as-yet-unknown spatial targets requiring conservation. However, global studies tracking megafauna and shipping occurrences are lacking. Here we combine satellite-tracked movements of the whale shark, Rhincodon typus, and vessel activity to show that 92% of sharks’ horizontal space use and nearly 50% of vertical space use overlap with persistent large vessel (>300 gross tons) traffic. Collision-risk estimates correlated with reported whale shark mortality from ship strikes, indicating higher mortality in areas with greatest overlap. Hotspots of potential collision risk were evident in all major oceans, predominantly from overlap with cargo and tanker vessels, and were concentrated in gulf regions, where dense traffic co-occurred with seasonal shark movements. Nearly a third of whale shark hotspots overlapped with the highest collision-risk areas, with the last known locations of tracked sharks coinciding with busier shipping routes more often than expected. Depth-recording tags provided evidence for sinking, likely dead, whale sharks, suggesting substantial “cryptic” lethal ship strikes are possible, which could explain why whale shark population declines continue despite international protection and low fishing-induced mortality. Mitigation measures to reduce ship-strike risk should be considered to conserve this species and other ocean giants that are likely experiencing similar impacts from growing global vessel traffic