Conserving intertidal habitats: what is the potential of ecological engineering to mitigate impacts of coastal structures?

Poster presentation: P-62Human ImpactsGlobally, coastal human population growth and urbanization continues in a fast pace, while climatic change leads to stormier seas and rising tides. Both driving forces jointly generate a strong and increasing demand for land reclamation and infrastructure protection in coastal areas which require engineered defence structures such as sea walls. This study aimed to review ecological impacts of coastal engineered structures on intertidal ecosystems, update the current status of ecological engineering to mitigate these impacts, and evaluate the effectiveness of such mitigations in relation to the conservation of intertidal habitats and biodiversity. Engineered structures alter important physical, chemical and biological processes of intertidal habitats, and ...postprin

Genomic landscape of lung adenocarcinoma in East Asians

Lung cancer is the world’s leading cause of cancer death and shows strong ancestry disparities. By sequencing and assembling a large genomic and transcriptomic dataset of lung adenocarcinoma (LUAD) in individuals of East Asian ancestry (EAS; n = 305), we found that East Asian LUADs had more stable genomes characterized by fewer mutations and fewer copy number alterations than LUADs from individuals of European ancestry. This difference is much stronger in smokers as compared to nonsmokers. Transcriptomic clustering identified a new EAS-specific LUAD subgroup with a less complex genomic profile and upregulated immune-related genes, allowing the possibility of immunotherapy-based approaches. Integrative analysis across clinical and molecular features showed the importance of molecular phenotypes in patient prognostic stratification. EAS LUADs had better prediction accuracy than those of European ancestry, potentially due to their less complex genomic architecture. This study elucidated a comprehensive genomic landscape of EAS LUADs and highlighted important ancestry differences between the two cohorts

Decreased thermal tolerance under recurrent heat stress conditions explains summer mass mortality of the blue mussel Mytilus edulis

Extreme events such as heat waves have increased in frequency and duration over the last decades. Under future climate scenarios, these discrete climatic events are expected to become even more recurrent and severe. Heat waves are particularly important on rocky intertidal shores, one of the most thermally variable and stressful habitats on the planet. Intertidal mussels, such as the blue mussel Mytilus edulis, are ecosystem engineers of global ecological and economic importance, that occasionally suffer mass mortalities. This study investigates the potential causes and consequences of a mass mortality event of M. edulis that occurred along the French coast of the eastern English Channel in summer 2018. We used an integrative, climatological and ecophysiological methodology based on three complementary approaches. We first showed that the observed mass mortality (representing 49 to 59% of the annual commercial value of local recreational and professional fisheries combined) occurred under relatively moderate heat wave conditions. This result indicates that M. edulis body temperature is controlled by non-climatic heat sources instead of climatic heat sources, as previously reported for intertidal gastropods. Using biomimetic loggers (i.e. 'robomussels'), we identified four periods of 5 to 6 consecutive days when M. edulis body temperatures consistently reached more than 30 °C, and occasionally more than 35 °C and even more than 40 °C. We subsequently reproduced these body temperature patterns in the laboratory to infer M. edulis thermal tolerance under conditions of repeated heat stress. We found that thermal tolerance consistently decreased with the number of successive daily exposures. These results are discussed in the context of an era of global change where heat events are expected to increase in intensity and frequency, especially in the eastern English Channel where the low frequency of commercially exploitable mussels already questions both their ecological and commercial sustainability.Funding Agency French Ministere de l'Enseignement Superieur et de la Recherche Region Hauts-de-France European Funds for Regional Economical Development Pierre Hubert Curien PESSOA Felloswhip Fundacao para a Ciencia e Tecnologia (FCT-MEC, Portugal) IF/01413/2014/CP1217/CT0004 National Research Foundation - South Africa 64801 South African Research Chairs Initiative (SARChI) of the Department of Science and Technology National Research Foundation - South Africainfo:eu-repo/semantics/publishedVersio

Reproductive behaviour of mangrove littorinid snails: how do males successfully mate with females?

Diverse reproductive behaviours in animals are developed to increase individual fitness. Some behavioural traits are selected to overcome environmental constraints, whereas others are evolved through sexual selection to maximize reproductive success. Most littorinid snails in the genus Littoraria inhabit mangrove trees in the Indo-Pacific region. Searching for mates within the complex 3-dimensional habitat of tree leaves, branches and trunks would appear a difficult task for these snails. Field studies of two co-occurring species in Hong Kong, Littoraria ardouiniana and L. melanostoma, however, showed that these species can successfully locate mates as overv 90% of mating pairs were 'true' pairs (a male mating with a conspecific female). This success is achieved through males of both species following mucus trails to locate conspecific females during the mating season. In both species, males were also capable of detecting the direction (polarity) of the trails of conspecific females. “Fighting” behaviour, which involves two males aggressively pushing each other when they encounter a female, was also observed in L. ardouiniana but not in L. melanostoma. Such aggressive behaviour during mate acquisition can be attributed to the male-biased sex ratio in natural populations of L. ardouiniana, which may drive competition for mates amongst males

Contrasting reproductive traits in two species of mangrove-dwelling littorinid snails in a seasonal tropical habitat

Previous studies on the reproductive biology of littorinid snails have focused on rocky shore species, investigating how these gastropods can achieve maximal reproductive success, as well as on processes of sexual selection. This study documented differences in the reproductive traits of two mangrove-dwelling littorinids, Littoraria ardouiniana and L. melanostoma, in Hong Kong. Reproductive activity of both species was most intense during the summer months. Mating pairs of the two species generally occurred in the tree canopies. Few false mating pairs (same sex or heterospecific pairs: <10%) were recorded, and members of both species showed size-assortative mating. Littoraria ardouiniana had a shorter reproductive season but a higher intensity of mating and higher seasonal fecundity, than did L. melanostoma. Members of both species showed bi-lunar periodicities of egg or larval release, synchronized with spring tides. Fecundity showed a strong positive relationship with body size in L. ardouiniana, but not in L. melanostoma. Females of L. ardouiniana released entire broods of larvae in a single brief event, whereas females of L. melanostoma released fewer eggs over 1-8 d. Release of larvae in L. ardouiniana involved a series of short bursts and was much faster than the trickle release of eggs in L. melanostoma. The contrasting reproductive traits in these two species represent different strategies to optimize reproductive success in mangrove habitats. © 2012, The American Microscopical Society, Inc.link_to_subscribed_fulltex

Mucus trail following as a mate-searching strategy in mangrove littorinid snails

Mate searching often involves chemical cues and is a key process in determining fitness in most sexually reproducing animals. Effective mate-searching strategies are, therefore, essential for individuals to avoid wasting resources as a result of misrecognition of mating partners. Marine snails in the genus Littoraria are among the most successful molluscan groups that live closely associated with mangroves. Their population densities are often low, and finding a mate within the complex three-dimensional habitat of tree leaves, branches and trunks requires an effective searching strategy. We tested whether males of L. ardouiniana and L. melanostoma located females by following their mucus trails. In the laboratory, male tracker snails followed mucus trails laid by conspecific female marker snails at a higher intensity compared with other marker-tracker sex combinations in the mating season, but not in the nonmating season, and this was more pronounced in L. ardouiniana. Male trackers did not move faster when following the trails of conspecific female markers compared with other sex combinations; however, tracker snails moved faster in the mating than in the nonmating season, although this might be related to temperature. In both species, males tracked females regardless of trail complexity, and the majority of male trackers were able to detect the direction (polarity) of the trails of conspecific females. Together with previous studies on rocky shore Littorina species, these findings suggest that sex pheromones are incorporated into mucus trails to facilitate the reproductive success of these snails. Mucus trail following is, therefore, an adaptive mate-searching strategy in intertidal gastropod molluscs, and potentially in other gastropod groups in which trail-following behaviour is prevalent. © 2011 The Association for the Study of Animal Behaviour.link_to_subscribed_fulltex

Sex on the beach: a cocktail of behavioural repertoires which drive size-assortative mating in rocky shore littorinids?

Session 7: General temperate reef scienceSymposium Theme: Ecological TransitionsSize-assortative mating occurs in a wide range of animal taxa and sexual selection is one of the major hypotheses proposed to explain the formation of this distinctive mating pattern. The rationale is that male mate preference for large, more fecund females, along with malemale competition (i.e., a physical advantage of large over small males in competing for large females), will result in a positive correlation between the sizes of mating males and females. This paradigm has been assumed to hold true for species of rocky shore littorinids, many of which exhibit size-assortative mating, despite any rigorous test of the model. This hypothesis was, therefore, tested in three littorinids: Echinolittorina malaccana, E. radiata and E. vidua on rocky shores at Cape d’ Aguilar, Hong Kong. Males of the three species generally trail followed, mounted and copulated with females similar or larger than their own body sizes (a form of size-dependent male mate preference); and copulated with larger females for longer durations. The males mating preference seems to be specific to their own body size (i.e., they selected females which were larger than their own size), which is a more dynamic approach than the traditional belief that all males simply prefer 'large' over small females. All three species also demonstrated male-male competition in the form of 'pushing' behaviour, where large males usually had a size advantage over small males in obtaining females to mate with. These findings support recent studies on mangrove littorinids and suggest that size-dependent male mate preference, along with male-male competition, may play an important role in driving size-assortative mating in littorinids and other animals that exhibit male mate choice