We have been working on the developmental and evolutionary sensory biology of coral reef fishes, North American freshwater fishes, cichlid fishes, deep sea fishes and elasmobranchs.
Sensory Biology of Coral Reef Fishes – Coral reef fishes live in well-lit waters and are generally considered to be visually-oriented. However, the diversity of sensory systems possessed by fishes and our appreciation of sensory integration in fishes demands that we ask fundamental questions about the non-visual senses and their roles in diverse behaviors.
- The Role of Larval Orientation Behavior in Population Connectivity – Sensory Ontogeny in a Coral Reef Goby (ongoing) – Most coral reef fishes (and most marine fishes) have a complex life history that includes the dispersal of planktonic eggs and pelagic larvae, with remarkable swimming abilities. Late stage larvae of coral reef fishes are known to respond to olfactory, auditory, and visual cues to change their behavior and navigate to their settlement sites on reefs, but the morphology and the pattern and timing of development of the sensory systems that underlie these behaviors are not well known. In this collaborative project with colleagues at Boston University and University of Miami, we are using a goby (Elacatinus lori) for the first integrated analysis of the developmental anatomy of multiple sensory systems (olfaction, taste, lateral line, hearing, vision) and larval orientation behavior in a coral reef fish. The ultimate goal is to understand how the different sensory systems contribute to the navigation behavior of pelagic larvae, and the role of navigation behavior in determining settlement patterns and population connectivity in coral reef fishes. Funded by NSF grant 1459546 (Ocean Sciences) and the George and Barbara Young Chair in Biology. See: Sensory Basis for Larval Fish Orientation Behavior page
- The Laterophysic Connection of Butterflyfishes and Implications for Communication and Social Behavior – A diversity of teleost fishes have convergently evolved associations of the swim bladder with the inner ear (otophysic connections) that enhance the reception of sound. We have described the comparative anatomy, development, and systematic significance of a unique swim bladder-lateral line linkage in butterflyfishes in the genus Chaetodon, the laterophysic connection, which has been shown to enhance sensitivity to acoustic stimuli in the context of critical behaviors, including territoriality and monogamous social systems in the field. Tricas and Webb (2016) reviewed their work on the morphology of the laterophysic connection, and on sound production and sound reception in butterflyfishes. Funded by NSF grants IBN 9603896 and IBN 0132607 to JFW.See: Butterflyfish Projectpage.
- The Lateral Line System of Damselfishes, Wrasses, and Parrotfishes – We examined the diversity and evolution of trunk canal phenotypes with respect to variation in body shape and lateral line scale morphology (Webb PhD Dissertation; Webb, 1990, in Copeia).
Flow Sensing in the Deep Sea: The Lateral Line System of Stomiiform Fishes – The deep sea is a hydrodynamically quiet environment characterized by low light levels or complete darkness. Specializations of the visual system are well known among mesopelagic fishes, in particular. Several groups of mesopelagic and bathypelagic fishes are known to have specializations of the lateral line system, but little had been known about the most speciose group of deep-sea fishes – the hatchetfishes, bristlemouths, and barbelled dragonfishes of the Order Stomiiformes. The lateral line system in these fishes was investigated for the first time using a range of morphological methods including histology, SEM, and µCT imaging. This work revealed a dramatic enhancement of the lateral line system (proliferation of superficial neuromasts) that had gone unnoticed until now (Marranzino and Webb, Zool. J. Linn. Soc., 2017). This discovery demands that the flow sensing capabilities of these fishes be considered in order to better understand the roles of these fishes in the ecology of the deep sea. Funded by an NSF Graduate Research Fellowship, Lerner-Gray Fund for Marine Research Grant (ANMH, NY) to graduate student Ashley Marranzino, and the George and Barbara Young Chair in Biology, and University of Rhode Island (A. Marranzino, MS Thesis 2016). See Deep Sea Lateral Line project page.
Development and Evolution of the Mechanosensory Lateral Line System – different taxa are being used to explore fundamental aspects of the developmental basis for phenotypic evolution of the lateral line system in bony fishes.
- North American Freshwater Fishes –This study will use three species of North American freshwater fishes to look at the developmental basis for the evolution of LL phenotypes. The silverjaw minnow (Ericymba buccata = Notropis buccatus) develops narrow canals on the dorsal surface of the head and widened canals on the ventral surface of the head (Reno 1971), an unusual example of regional specialization of the lateral line system, which is likely adaptive for feeding on invertebrates in sandy sediments (not unlike the cichlid Aulonocara; see below). Another North American minnow, Pimephales promalas(the fathead minnow), and a salmonid, brook trout (Salvelinus fontinalis) will be used to provide a comparative context. Both the developmental basis for phenotypic variation and its behavioral consequences are being examined. Funded by NSF Graduate Research Fellowship and URI Graduate School EGRA to graduate student Aubree Jones.
- African Cichlids – Representatives of two genera of Lake Malawi (Africa) cichlid fishes (Aulonocara [widened canals] and Tramitichromis [narrow canals]) were used for comparative anatomical, developmental, and behavioral studies that address fundamental issues in post-embryonic lateral line development, diversification of lateral line phenotypes (narrow, widened canals), and functional evolution of the lateral line system. We described the morphology and development of the lateral line system of Aulonocara and Tramitichromis (EA Becker, MS Thesis; Becker, et al., 2016; L Carter, MS Thesis; JW Johnstone, MS Thesis), explored the role of heterochrony in phenotypic evolution (Webb, et al., 2014; Bird and Webb, 2014) established the role of the lateral line system in the detection of benthic prey in Aulonocara, and distinct differences in the sensory basis for prey detection in Aulonocara and Tramitichromis using live prey and artificial water flows (MAB Schwalbe PhD Dissertation; Schwalbe et al., 2012, 2016; Schwalbe & Webb, 2014, 2015) . Funded by NSF grant IOS 0843307, RI NSF EPSCoR, and the University of Rhode Island. See: Cichlid Project page.
Lateral Line Development in Elasmobranch Fishes – We are studying the development of the lateral line canal system in the little skate, Leucoraja erinacea. In contrast to the bony fishes, the cranial lateral line canals in elasmobranch fishes are not associated bone, but are contained in the soft tissue of the dermis surrounding the elements that compose the cartilaginous skull of these fishes. Furthermore, the pattern of development of the lateral line system in elasmobranchs contrasts with that in bony fishes in fundamental ways. The study of this contrast will shed light on how lateral line development evolved with the divergence of the cartilaginous (elasmobranch) and bony fishes hundreds of millions of years ago. This work has been carried out at the Marine Biological Laboratory (Woods Hole) in collaboration with Dr. Andrew Gillis (Cambridge University, UK). Funded by a Laura and Arthur Colwin Endowed Summer Research Fellowship at the MBL and the University of Rhode Island. See Skate Project page.