Composition and behavior of mixed-species foraging groups of reef fish in the Lakshadweep islands, India

Mixed-species foraging groups of reef fishes, although relatively common in occurrence, have historically received little attention. Most studies on this topic have been descriptive accounts of specific associations. In this study, we collected data on mixed-species foraging groups seen in the Lakshadweep islands, resulting in a dataset of 1289 groups. Data was collected from both reefs and lagoons of three islands (Kadmat, Kavaratti, and Agatti) within the Lakshadweep Archipelago over a period of three years. Cluster analysis revealed nine categories based on species composition in groups: parrotfish, juveniles, surgeonfish (small), surgeonfish (large), Anampses spp., wrasses, Parupeneus macronema, Parupeneus barberinus, and other goatfish groups. The clusters are named based on the nuclear species or most frequently seen species within the groups. These groups are distinct not only in terms of composition but also other parameters such as behavior (shoaling or attendant groups), habitat affinity, and group cohesion. Groups comprising herbivorous species such as parrotfish and surgeonfish were almost entirely shoaling in nature (large groups without nuclear individuals), whereas goatfish and wrasses tended to form smaller attendant associations. Groups also occupied different habitat types; for example, parrotfish and P. barberinus groups were seen mostly in lagoons while surgeonfish, wrasses, and P. macronema groups were more abundant on reefs. Our findings suggest that mixed-species foraging groups in fishes are comprised of distinct compositional categories that vary in behavior, cohesion, and habitat affinity.

First record of four whiteflies (Hemiptera: Aleyrodidae) and their natural enemies in Lakshadweep Islands, India

Four whitefly species including three invasive whitefly species viz., rugose spiralling whitefly, Aleurodicus rugioperculatus Martin (Hemiptera: Alyrodidae) on 10 host plants; Bondars nesting whitefly, Paraleurodes bondari Peracchi on seven host plants, woolly whitefly, Aleurothrixus floccosus (Maskell) on guava and Bemisia euphorbiae (David & Subramaniam) on two plants were reported for the first time in Lakshadweep. Parasitoid, Encarsia guadeloupae Viggiani (Hymenoptera: Aphelinidae) and predators viz., Pseudomallada (=Dichochrysa) astur (Neuroptera: Chrysopidae) and Cybocephalus indicus (Coleoptera: Nitidulidae) were found associated with these whiteflies. Distribution of whiteflies along with their host plants and natural enemies in Lakshadweep Islands are given.

Seagrass Ecosystems of India as Bioindicators of Trace Elements

Seagrasses are considered as efficient bioindicators of coastal trace element contamination. This chapter provides an overview on the trace element accumulation, tolerance and biomonitoring capacity of the various seagrass species distributed along the coast of India. A total of 10 trace elements are reported in seagrasses, 11 in sediment and nine in the water column from India. From the 11 seagrass species studied, 60% of research have focused on Syringodium isoetifolium, Cymodocea serrulata, Cymodocea rotundata and Halophila ovalis. 78% of seagrass trace element research in India is from Palk bay and Gulf of Mannar (GOM), Tamil Nadu and 16% from Lakshadweep Islands. Out of the 10 trace elements, Cd, Cu, Pb and Zn are the most studied in seagrass, Fe, Mn, Ni and Pb in sediment and Cu, Fe, Mg, Ni and Zn in the water column. Accumulation capacity of various trace elements in seagrass were species-specific. S. isoetifolium have the highest concentration of Cd and Mg at Palk bay and Lakshadweep Islands respectively. The concentration of Cu was higher in C. serrulata at GOM. Halodule uninervis and Halophila decipens have the highest concentration of Co, and Cr, Ni, Pb and Zn from Lakshadweep Islands. The highest concentration of Fe and Mn were highest in Halophila beccarii and H. ovalis from the coast of Goa and Palk bay respectively. Threshold levels (>10 mg L-1) of Cd, Cu, Pb and Zn were observed for C. serrulata, H. ovalis, H. uninervis and T. hemprichii, that can affect the Photo System -II of these seagrasses and exert cellular stress leading to seagrass loss and die-off. High concentration of these elements can exert negative impacts on seagrass associated trophic assemblages and ecosystem functioning. Seagrasses of India can be utilized as bioindicators of coastal trace element contamination but the associated toxicity and human health risks needs further investigation.

Urocaridella arabianensis n. sp., a new Palaemonid shrimp (Crustacea, Decapoda, Palaemonidae) from Lakshadweep Islands, India with taxonomic comparison on the genus Urocaridella Borradaile, 1915

A new species of the genus Urocaridella Borradaile, 1915, Urocaridella arabianensis n. sp. is described and illustrated based on fifty-five specimens collected from the reef regions of Agatti Island, Lakshadweep, Arabian Sea. Urocaridella arabianensis n. sp. is morphologically close to U. pulchella Yokes & Galil, 2006, reported from the Mediterranean Sea. However, the present specimen is clearly distinguished with its rostrum length, which is 1.7 to 2.1 times as long as carapace, 10 ventral rostral teeth, carpus of 1st pereopod is 2.5 times long as palm, carpus of 2nd pereopod is 1.8 times as long as palm, presence of a spine in latero-middle of the fourth and fifth abdomens and the sixth abdominal segment is 2.3 times long as the fifth segment. Partial segment of the mitochondrial COI, 16S rRNA and nuclear gene 18S rRNA and H3 indicates that the new species is sister to a clade comprising of U. pulchella, U. antonbruunii and U. degravei. The pair wise genetic distance of COI showed great distance with the closest congeneric species.

New records of brittle stars (Echinodermata: Ophiuroidea) from the Lakshadweep atolls, northern Indian Ocean, with notes on Indophioderma ganapatii Sastry, Marimuthu & Rajan, 2019

The paper presents three new records of brittle stars for Indian waters, collected from the Lakshadweep atolls (northern Indian Ocean)—Ophiarachnella septemspinosa (Müller & Troschel, 1842), Ophiocoma cynthiae Benavides-Serrato & O’Hara, 2008 & Ophiomoeris obstricta (Lyman, 1878). Further, this paper also discusses the validity of two recently described taxa from this archipelago, the genus Indophioderma with the species Indophioderma ganapatii Sastry, Marimuthu & Rajan, 2019. A checklist of brittle stars reported so far from the Lakshadweep Islands is provided, which includes 40 valid species—32 from shallow (reef) areas and 8 deep-sea (>200m) species.