Twenty-Five Years of Domoic Acid Monitoring in Galicia (NW Spain): Spatial, Temporal and Interspecific Variations

Prevalence, impact on shellfish resources and interspecific, spatial, and temporal variabilities of domoic acid (DA) in bivalves from Galicia (NW Spain) have been studied based on more than 25 years of monitoring data. The maximum prevalence (samples in which DA was detected) (100%) and incidence (samples with DA levels above the regulatory limit) (97.4%) were recorded in Pecten maximus, and the minimum ones in Mytilus galloprovincialis (12.6 and 1.1%, respectively). The maximum DA concentrations were 663.9 mg kg−1 in P. maximus and 316 mg kg−1 in Venerupis corrugata. After excluding scallop P. maximus data, DA was found (prevalence) in 13.3% of bivalve samples, with 1.3% being over the regulatory limit. In general, the prevalence of this toxin decreased towards the North but not the magnitude of its episodes. The seasonal distribution was characterized by two maxima, in spring and autumn, with the later decreasing in intensity towards the north. DA levels decreased slightly over the studied period, although this decreasing trend was not linear. A cyclic pattern was observed in the interannual variability, with cycles of 4 and 11 years. Intoxication and detoxification rates were slower than those expected from laboratory experiments, suggesting the supply of DA during these phases plays an important role.

Re-evaluating vocal production learning in non-oscine birds

The study of vocal production learning in birds is heavily biased towards oscine songbirds, making the songbird model the reference for comparative studies. However, as vocal learning was probably ancestral in songbirds, interspecific variations might all be variations on a single theme and need not be representative of the nature and characteristics of vocal learning in other bird groups. To assess the possible mechanisms of vocal learning and its evolution therefore requires knowledge about independently evolved incidences of vocal learning. This review examines the presence and nature of vocal production learning in non-songbirds. Using a broad definition of vocal learning and a comparative phylogenetic framework, I evaluate the evidence for vocal learning and its characteristics in non-oscine birds, including well-known vocal learners such as parrots and hummingbirds but also (putative) cases from other taxa. Despite the sometimes limited evidence, it is clear that vocal learning occurs in a range of different, non-related, taxa and can be caused by a variety of mechanisms. It is more widespread than often realized, calling for more systematic studies. Examining this variation may provide a window onto the evolution of vocal learning and increase the value of comparative research for understanding vocal learning in humans. This article is part of the theme issue ‘Vocal learning in animals and humans’.

Molecular identification of Gracilaria species (Gracilariales, Rhodophyta) obtained from the South Coast of Java Island, Indonesia

Meinita MDN, Akromah N, Andriyani N, Setijanto, Harwanto D, Liu T. 2021. Molecular identification of Gracilaria species (Gracilariales, Rhodophyta) obtained from the South Coast of Java Island, Indonesia. Biodiversitas 22: 3046-3056. The study of seaweeds diversity and species identification is an important component of marine resource management. However, seaweed identification based on morphological characteristics has several limitations. Besides, DNA barcodes or the partial sequences of cytochrome c oxidase I (COX1) have been proved to identify seaweeds at the species level. To date, Gracilaria species molecular diversity has not been studied in the South Coast of Java Island. Hence, this study aimed to identify the Gracilaria spp. obtained from 6 different beaches along the South Coast of Java, based on the COX1 gene. COX1 gene utilization for identifying and observing the genetic diversity, both intraspecific (genetic variation within species) and interspecific (variations between species) of Gracilaria species in this study has produced good results. A total of 13 seaweed samples collected from beaches in this study were identified as Gracilaria salicornia, G. edulis, G. firma, and G. textorii. The results of genetic diversity analysis conducted using the COX1 gene showed the intraspecific diversity of G. edulis obtained from the beaches of Kondang Merak, Kukup, Nusakambangan, and Karapyak was included in the moderate diversity category. Also, the intraspecific diversity of G. salicornia obtained from the beaches of Kondang Merak, Kukup, and Nusakambangan was included in the moderate diversity category, while the intraspecific diversity of G. textorii from Menganti and Karapyak Beach had no diversity.

The relationship between altitudinal gradients, diversity, and body size in a dung beetle (Coleoptera: Scarabaeinae: Onthophagus) model system

Mountainous regions represent an excellent model to test ecological hypotheses encompassing assemblage diversity and body traits of species. Among insects, there is no uniform body size pattern across temperature gradients, suggesting that processes controlling body size may differ among species. The aim of this study was to explore diversity and body size patterns of dung beetle species of the genus Onthophagus Latreille, 1802 across altitudinal gradients at two mountains in Mexico. Tropical mountain species were sampled from 2200 to 3400 m a.s.l. In both mountains, there was a decrease of richness and abundance of Onthophagus with increasing altitude. There were contrasting relationships between beetle body size and altitude, which varied depending on the data set analyzed. Furthermore, interspecific variations of body size were not related to the number of altitudinal bands recorded by each species. Species from high altitudes were also recorded at lower mountain altitudes, suggesting that diversity at the highest altitudes represents a subgroup of lowland diversity. This may indicate that the fauna inhabiting higher elevations could be the most eurytopic one. Here we present an example of an assemblage that partially contradicts Bergmann’s rule, with contrasting effects of altitude on dung beetle body size.