Arthropoda

Environmental DNA (eDNA) offers a promising, non-invasive approach for monitoring infectious agents in aquaculture. While molecular techniques for detecting shrimp pathogens are well established in host tissues, there is a lack of standardized protocols for pathogen detection from environmental samples using conventional PCR. In this study, we developed and validated a universal conventional PCR protocol for monitoring DNA from major viral and bacterial shrimp pathogens within pond water and sediment samples. The method was applied to two commercial shrimp farms in Mexico, where eDNA was extracted from field-collected water and sediment. Using published primer sets, we successfully amplified DNA sequences corresponding to six key pathogens—Infectious hypodermal and hematopoietic necrosis virus (IHHNV), Baculovirus penaei (BP), Monodon baculovirus (MBV), Shrimp hemocyte iridescent virus (SHIV), Candidatus Hepatobacter penaei (NHP-B), and Acute hepatopancreatic necrosis disease (AHPND)-causing Vibrio spp.—in environmental samples. Sequencing of PCR amplicons confirmed 93–100% identity to previously reported pathogen strains, highlighting the method’s reliability. Pathogen detection rates varied by site, sample type, and date, with the percentage of positive samples ranging from 11.1% to 77.7%. Notably, this is the first report of SHIV DNA detection from environmental samples in the Americas, highlighting its value for pathogen surveillance even in the absence of documented outbreaks. This protocol offers a cost-effective and scalable tool for pathogen surveillance in shrimp aquaculture, enhancing early disease detection and contributing to improved biosecurity and risk assessment frameworks.

Five new species of Schizomida are described from the Ecuadorian Andes and the Amazonian ecoregion in three different genera: in Colombiazomus, Colombiazomus karsticus n. sp. (female); in Hansenochrus, Hansenochrus maicun. sp. (male) and Hansenochrus pastaza n. sp. (female); and in Surazomus, Surazomus colonso, n. sp. (male, female) and Surazomus yasunin. sp. (male, female). A distribution map of all newly described species is presented.

In penaeids, the major yolk protein precursor vitellogenin is synthesized in both the hepatopancreas and the ovary. While ovarian vitellogenin expression is clearly regulated by hormones from the X-organ/sinus gland in the eyestalk, regulation in the hepatopancreas remains poorly understood. Here, we performed transcriptome profiling stratified by endogenous hepatopancreatic vitellogenin gene (Maj-Vg1) expression levels in immature kuruma prawn Marsupenaeus japonicus. Pathway enrichment analysis identified the insulin, mechanistic target of rapamycin (mTOR), glucagon, and AMP-activated protein kinase (AMPK) pathways as candidate modules associated with the control of hepatopancreatic Maj-Vg1 expression. Analysis of differentially expressed genes identified slit-like (Slit) and calreticulin (Calr) as genes potentially involved in the regulation of Maj-Vg1 expression. In ex vivo hepatopancreas explants, insulin-like peptide 1 from this species induced Maj-Vg1 and was accompanied by the upregulation of lipogenic markers (Max-like protein X (Mlx) and acetyl-CoA carboxylase (Acc)), consistent with vitellogenin’s lipid-transport role. Expression patterns of Calr, tuberous sclerosis complex 1 and 2 (Tsc1 and Tsc2) suggest regulatory inputs beyond insulin signaling, indicating context-dependent regulation. Taken together, these data identify metabolic status as an important contributor to hepatopancreatic Maj-Vg1 expression and define further research targets, including mTOR, AMPK, glucagon, and the Slit/Roundabout axis, for understanding vitellogenesis in penaeids.