Longer Spines Research Articles

Pollen morphology for successful pollination dependent on pollinator taxa in a generalist plant: relationship with foraging behavior.

Pollen morphology varies at inter- and intraspecific levels. Its interaction with pollinator behavior and morphology determines the probability of successful pollination. We tested whether pollen morphology promoting successful pollination differs depending on pollinator taxa in a generalist shrub, Weigela hortensis (Caprifoliaceae). We identified flower visitors carrying pollen from anthers to stigmas and compared the spine length and diameter of the pollen grains they carried. We found that pollen on the bodies of bumble bees and hunch-back flies and the scopae of small bees (including andrenid bees) contributed to seed production. Pollen grains on the bodies of bumble bees had longer spines than those on the scopae of andrenid bees or the bodies of hunch-back flies. Pollen grains on the bodies of bumble bees and the scopae of andrenid bees had larger diameters than those on hunch-back flies. Bumble bees collected pollen grains with shorter spines and larger diameters on their corbiculae while andrenid bees collected pollen grains with shorter spines and intermediate diameters on their scopae. The differences in morphology of pollen carried by pollinators reflected the tendency of bees to collect pollen with specific morphology into corbiculae/scopae. Our findings suggest that pollen morphology has diversified to facilitate successful pollination by pollinating partners.

Fishes associating with the echinoids Diadema setosum and Echinothrix calamaris (Diadematoida: Diadematidae) in the Phi Phi Islands of southwestern Thailand

Many fish species are known to associate with echinoids. We studied the frequency of fishes associating with the diadematid Black Longspine Urchin Diadema setosum and Banded Sea Urchin Echinothrix calamaris in the Phi Phi Islands of southwestern Thailand during July 17–20, 2022. A total of 1373 fish individuals of 20 species associated with 1157 D. setosum, and 11 fish individuals of seven species associated with 76 E. calamaris. The proportion of fish individuals per echinoid host was 8.2 times higher for longer-spined D. setosum (1.19) than for E. calamaris (0.14), and the proportion of echinoids hosting one or more fish was 2.5 times higher for D. setosum (22.9%) than for E. calamaris (9.2%), supporting the hypothesis that fishes prefer to associate with echinoid species with the longest spines, which potentially provide more protection against predators. All fishes associating with echinoids were small (<10 cm); most were adults, but for some species, all were juveniles. All fishes were facultative associates of echinoids. Only three fish species had been previously reported associating with D. setosum and none with E. calamaris; the remaining fish species represent new records of association, including 17 for D. setosum and seven for E. calamaris.

Maternal influence on the larval morphometry of the brush-clawed shore crab Hemigrapsus takanoi (Decapoda: Brachyura)

The morphology of larvae is a key factor influencing their behaviour, performance and ultimately their survival. There is evidence indicating a significant morphological variability among broods, and that this may be related to the size or conditions of the mother. However, this maternal influence is not consistent across decapod crustaceans. Using 35 broods from different mothers of the crab Hemigrapsus takanoi collected in the same locality of inner Tokyo Bay and at the same time, we tested the hypothesis that there is a positive relationship between the size of the mother and the progeny’s morphology. Our results indicate that different patterns in the length of the lateral, rostral and dorsal spines differentiated two distinct morphogroups of larvae. These morphogroups were linked to the size of the mother, showing that larger mothers produced bigger larvae with longer carapace spines. It is possible that larger size and longer spines can influence swimming performance and predator avoidance, respectively. These relationships should be tested in future experimental studies.

The role of the length spines of echinoids in their association with crustacean and fish in Los Cabos, Baja California Sur, Mexico

Introduction: Echinoids (sea urchins) provide shelter for a variety of facultative or obligatory ectosymbionts. Objective: To evaluate the hypothesis that decapods and fishes prefer to associate with echinoid individuals and species that have longer spines. Methods: We visually studied the frequency of decapod crustaceans and fishes associated with echinoids in shallow water (&lt; 4 m) and deeper water (5-20 m) at Los Cabos, Baja California Sur, Mexico, during 1-6 January 2019. Results: We inspected 1 058 echinoids of six species. Five decapod species associated with three species of echinoids. When compared with other echinoid species, in shallow water, decapods associated 5.1 times more often with the longest-spined echinoid Diadema mexicanum (7.0 times more decapods per individual D. mexicanum); in deeper water, association frequency was similar for all echinoid species. Fourteen fish species associated with four echinoid species. In shallow water, fishes associated 2.6 times more with D. mexicanum (4.5 times more fishes per individual). There was no preferred echinoid species in deeper water. Longer-spined D. mexicanum had more decapods and fishes. Associations were more frequent in shallow water. Multiple individuals and species of decapods and fish often associated together with a single D. mexicanum. The decapod that presumably is Tuleariocaris holthuisi showed a possible obligatory association with one of the equinoids (D. mexicanum); the other decapods and all fish species are facultative associates. Conclusion: Our results support the hypothesis that decapods and fishes associate most frequently with echinoid with the longest spines, presumably to reduce the risk of predation.

Defensive spines are associated with large geographic range but not diversification in spiny ants (Hymenoptera: Formicidae: Polyrhachis)

AbstractSeveral prominent evolutionary theories propose mechanisms whereby the evolution of a defensive trait or suite of traits causes significant shifts in species diversification rate and niche evolution. We investigate the role of cuticular spines, a highly variable morphological defensive trait in the hyperdiverse ant genus Polyrhachis, on species diversification and geographic range size. Informed by key innovation theory and the escape‐and‐radiate hypothesis, we predicted that clades with longer spines would exhibit elevated rates of diversification and larger range sizes compared to clades with shorter spines. To address these predictions, we estimated phylogenetic relationships with a phylogenomic approach utilizing ultraconserved elements and compiled morphological and biogeographic trait databases. In contrast to the first prediction, we found no association between diversification rate and any trait (spine length, body size and range size), with the sole exception of a positive association between range size and diversification in one of three trait‐based diversification analyses. However, we recovered a positive phylogenetic correlation between spine length and geographic range size, suggesting that spines promote expanded geographic range. Notably, these results were consistent across analyses using different phylogenetic inference approaches and spine trait measurement schemes. This study provides a rare investigation of the role of a defensive trait on geographic range size, and ultimately supports the hypothesis that defensive spines are a factor in increased range size in Polyrhachis ants. Furthermore, the lack of support for an association between spines and diversification, which contrasts with previous work demonstrating a positive association between spines and diversification rate, is intriguing and warrants further study.

Morphological defences and defence–cost trade‐offs in Daphnia in response to two co‐occurring invertebrate predators

Abstract Inducible morphological defences are crucial for understanding predator–prey interactions. Such defences have been mostly studied in a single‐predator context, ignoring the fact that prey organisms are often exposed to multiple predators. In deep peri‐Alpine European lakes, the keystone grazer Daphnia coexists with two cladoceran predators, Bythotrephes longimanus and Leptodora kindtii. Up to now, life history and morphological responses of Daphnia to these two predators have not been analysed systematically. We studied the responses of two life history (age at first reproduction, and offspring production) and five morphological traits (body size, body width, head size, spina size, and eye diameter) of eight Daphnia galeata clones to the presence of Bythotrephes and Leptodora in a common garden experiment. We compared each response trait between treatments using linear mixed models, and investigated the covariation between defence traits and demographic costs (neonate production) for the two predators. Our results show that the responses of Daphnia are predator‐ and trait‐specific. Daphnia developed a typical helmet and a larger eye only in the presence of Bythotrephes, not in the presence of Leptodora. In contrast, both predators induced larger body sizes and longer spines. Age at first reproduction was latest and demographic costs were highest in the Bythotrephes treatment, suggesting that the development of a helmet exceeds the costs of spina elongation. The responses of Daphnia clones revealed a defence‐cost trade‐off for helmet formation in the Bythotrephes, and for spina elongation in the Leptodora treatment. Hence, despite Bythotrephes and Leptodora being closely related co‐occurring predators, Daphnia responds with a unique combination of trait changes and defence‐cost trade‐offs to the two predators. The presence of predator‐specific clonal defence‐cost trade‐offs suggests that the presence of these invertebrate predators can drive different evolutionary processes in natural zooplankton communities. Disentangling the evolutionary ecology of phenotypic responses of prey species to co‐occurring predators will require multi‐trait, multi‐clone studies of induced antipredator defences.

A New Species of Ophioglossolambis Dekkers, 2012 from the Mascarene Islands (Mollusca: Gastropoda: Strombidae)

This paper describes a new species of Ophioglossolambis Dekkers, 2012 from the Mascarene Islands (Mauritius, Rodrigues, and Réunion) and Saint Brandon (also known as Cargados Carajos) Shoals in the western Indian Ocean as Ophioglossolambis itsumiae. It is separated from Ophioglossolambis digitata (Perry, 1811), its closest congener from the coastal waters of Madagascar and East Africa, by its typically larger and broader build, longer spines, lighter coloration, a more flared labral flange, and, most especially, very compact and short spire.

The story of the Malagasy devils (Orthoptera, Tetrigidae): Holocerus lucifer in the north and H. devriesei sp. nov. in the south?

Madagascar is home to some of the largest and most colorful pygmy grasshoppers (Tetrigidae) in the world, known as ‘Malagasy Metrodorinae’. Among them, Devil’s pygmy grasshoppers (genus Holocerus Bolívar, 1887) are unique in having two long spines on the back, which are modified internal lateral pronotal carinae. The genus Holocerus was composed of two species – H. lucifer (Serville, 1838) and H. taurus Rehn, 1929 syn. nov., but here it is evidenced that the latter represents a junior synonym of the former. Simultaneously, H. devrieseisp. nov. is described as a species new to science. Holocerus lucifer is a northern species of paler coloration and longer spines (distributed from Marojejy and Maroantsetra in the north to Zahamena in the south), whereas H. devrieseisp. nov. represents the southern and darker species (distributed from Vohimana and Andasibe-Mantadia in the south to the Antongil Bay in the north). There are potential overlaps in the distribution of the two species, but without more georeferenced localities, it is impossible to discriminate whether they occur only sympatrically or also syntopically.

Spine and dine: A key defensive trait promotes ecological success in spiny ants.

A key focus of ecologists is explaining the origin and maintenance of morphological diversity and its association with ecological success. We investigate potential benefits and costs of a common and varied morphological trait, cuticular spines, for foraging behavior, interspecific competition, and predator–prey interactions in naturally co‐occurring spiny ants (Hymenoptera: Formicidae: Polyrhachis) in an experimental setting. We expect that a defensive trait like spines might be associated with more conspicuous foraging, a greater number of workers sent out to forage, and potentially increased competitive ability. Alternatively, consistent with the ecological trade‐off hypothesis, we expect that investment in spines for antipredator defense might be negatively correlated with these other ecological traits. We find little evidence for any costs to ecological traits, instead finding that species with longer spines either outperform or do not differ from species with shorter spines for all tested metrics, including resource discovery rate and foraging effort as well as competitive ability and antipredator defense. Spines appear to confer broad antipredator benefits and serve as a form of defense with undetectable costs to key ecological abilities like resource foraging and competitive ability, providing an explanation for both the ecological success of the study genus and the large number of evolutionary origins of this trait across all ants. This study also provides a rare quantitative empirical test of ecological effects related to a morphological trait in ants.

Untangling the Gordian knot\u2014further resolving the super-species complex of 300-million-year-old xiphosurids by reconstructing their ontogeny

The group Xiphosurida (horseshoe “crabs”) is today only represented by four species. However, in the fossil record, several dozen species have been described, especially from the Carboniferous (about 300 million years ago). Several species have been interpreted as representatives of Euproops or Belinurus, but there is ongoing discussion which of these species are valid and how they can be differentiated. Recent studies suggested that differences in the timing of individual development could provide information for species distinction, exemplified by studies on Euproops danae (Mazon Creek, USA) and Euproops sp. (“Piesproops”; Piesberg, Germany). For this study, we reinvestigated all Carboniferous xiphosurids from the British Coal Measures stored in the collections of the Natural History Museum London. Size comparisons of the specimens revealed nine size groups; the smaller specimens were originally labelled as Belinurus, the larger ones as Euproops. The nine size groups exhibit five different morphotypes differing in structures surrounding the posterior shield (= thoracetron): spines of different lengths and, in larger specimens, a more or less developed flange. Two of these morphotypes show significantly longer spines than the remaining specimens and could be conspecific as E. anthrax. The remaining specimens are interpreted as growth series of another species, presumably of E. rotundatus. An ontogenetic flange formation is also known from E. danae and the “Piesproops”, but the timing differs between all three species. In E. rotundatus, the flange develops rather late, but then comparably abruptly, which makes this development more metamorphic in relation to development in the other species.

New species of Duplominona Karling, 1966 and Pseudominona Karling, 1978(Platyhelminthes: Proseriata) from the Caribbean.

Nine new species of Duplominona and one new Pseudominona (Platyhelminthes, Proseriata, Monocelididae) are described from the Caribbean coast of Panama and from Puerto Rico. Duplominona aduncospina n. sp.; D. terdigitata n. sp.; D. pusilla n. sp.; D. bocasana n. sp. (from Panama) and D. dissimilispina n. sp.; D. chicomendesi n. sp.; D. macrocirrus n. sp.; D. diademata n. sp.; D. puertoricana n. sp. (from Puerto Rico) can be distinguished from the numerous congeneric species based on fine details of the sclerotized structures of the copulatory organ. Duplominona aduncospina n. sp. is characterised by a cirrus provided with 3-4 rows of recurve spines, 2-3 μm long. D. terdigitata n. sp. shows a tripartite tail, and needle-shaped cirrus spines, 1.5-9 μm long. Cirrus spines of D. pusilla n. sp. are scale-like, 1.5-3 μm long. D. bocasana n. sp. has triangular spines, 1.5-6 μm long. D. dissimilispina n. sp. has needle-shaped spines, 3.5-15 μm long. D. chicomendesi n. sp. has a small cirrus, with few, strongly curved spines, 2-7.5 μm long. D. macrocirrus n. sp. has a large cirrus, provided with spines 3-9 μm long, with the longest spines placed medially. D. diademata n. sp. has a cirrus with two separate spiny areas, with spines 7-13 μm long. D. puertoricana n. sp. has a very long cirrus, with poorly sclerotised proximal spines, and distal spines to 6 μm long. A taxonomic key of the genus Duplominona is provided. Pseudominona cancan n. sp. from Panama differs from P. dactylifera from Bermuda, the only species known in the genus so far, for its shorter cirrus and fewer, triangular spines 3-5 μm long, and for the position of the vagina, close to mouth. A specimen attributed to P. dactylifera collected in Puerto Rico is described. Distribution of the new species suggests a complete separation of Panamanian and Puerto Rican proseriate fauna, confirming previous reports of restricted ranges and high endemicity of mesopsammic Platyhelminthes.

Prosopis andicola (Algarobia, Caesalpinioideae, Leguminosae), a new combination and rank, and P. calderensis, a new species for mesquite populations from Southern Peru

Prosopis andicola is presented as a new combination and rank deduced from P. laevigata var. andicola. Prosopis andicola differs from P. laevigata var. laevigata by having longer spines, leaves with one pair of pinnae, fusiform-acute leaflets, and solitary, falcate and frequently twisted legumes at maturity, with bigger seeds. Additionally, a new species P. calderensis is described. Prosopis calderensis, differs from these two species by its branches often with sugary excretions, glaucous leaves, a longer distance between leaflets on the rachis, anthers frequently purple, falcate and often twisted legumes at maturity in groups up to seven. Prosopis laevigata are trees distributed especially in the central plateau and hillsides of Mexico, while P. andicola are shrubs from Southern Peru and Bolivia, and P. calderensis are shrubs or cultivated trees from the occidental deserts of western Peru.

Short communication: Morphological characteristics of flower and fruit in several rambutan (Nephelium lappaceum) cultivars in Serang City, Banten, Indonesia

Abstract. Windarsih G, Efendi M. 2019. Morphological characteristics of flower and fruit in several rambutan (Nephelium lappaceum L.) cultivars in Serang City, Banten, Indonesia. Biodiversitas 20: 1442-1449. Indonesia is one of the centers of diversity of rambutan in the world with 22 species. Compared to other species, Nephelium lappaceum L. is mostly cultivated species. This study aimed to identify the generative morphological variation in several rambutan cultivars in the area of Serang City, Banten Province. The plant materials used were five cultivars of rambutan, Parakan, Rapiah, Aceh, Sinyonya, wild type, and male trees. In each plant, three bunches of inflorescence were taken, and then the flowers from each bunch were observed when the flowering phase was open (blooming). In addition, 3-5 fruit bunches were taken per plant, and then 3-5 fruits per bunch were observed. Based on the results obtained, it can be concluded that there is monoecious plants of rambutan (Aceh, Rapiah, wild type), and dioecious plant (male tree). In a monoecious plant, it produces the hermaphrodite flowers, whereas, in a dioecious plant, it just produces the male flowers. In the hermaphrodite flower, it is composed of pedicel, tepal, stamen, and pistil, while the male flower does not have pistil. The Aceh cultivar has the longest average fruit bunch (22.90 cm), Rapiah has highest number of fruit per bunch (15.86 fruits), Parakan has highest spine density (11.64 strands per 1x1 cm2) and longest spine (13.2 mm), Rapiah has a shortest average spine (3.4 mm) with a stiff texture, Rapiah and Aceh have a thickest of fruit rind (3.3 mm). Aceh has the largest size and weight of fruit with the fruit length 4.62 cm, fruit diameter 3.83 cm, fruit weight 37.42 g, weight of fruit rind 17.51 g, weight of aryl 17.94 g, and thickness of aryl 7.7 mm. From a dendrogram analysis, the five cultivars had a similarity distance coefficient from 40% to 69%. Parakan and Sinyonya had highest similarity distance (69%), while Aceh was separated from other cultivars with a similarity distance 40%.

Building global change resilience: Concrete has the potential to ameliorate the negative effects of climate-driven ocean change on a newly-settled calcifying invertebrate

Global climate change is driving sea level rise and increasingly frequent storm events, which are negatively impacting rapidly-growing coastal communities. To mitigate these impacts, coastal infrastructure must be further protected by upgrading hard defences. We propose that incorporating pH-buffering materials into these upgrades could safeguard marine organisms from the adverse effects of ocean acidification and ocean warming during the vulnerable transition from planktonic larvae to benthic juveniles. To test this, we examined the effects of ocean warming (24 or 27 °C), ocean acidification (pH 8.1, 7.9, 7.7), and substratum (concrete, greywacke, granite) in all combinations on the settlement success of an ecologically and commercially important sea urchin, Tripneustes gratilla. Low pH (7.9, 7.7) generally reduced the quantity and size of juveniles four weeks post-settlement, although this was partially ameliorated by increased temperature (24 vs. 27 °C). In the warmed and acidified treatments, settlement rates were lower on concrete than granite or greywacke, but two weeks post-settlement, juveniles on concrete were larger, and had longer spines and higher survival rates than on greywacke or granite, respectively. The benefits provided by concrete to newly-settled juveniles may be related to alkali chemicals leaching from concrete buffering low pH conditions in surrounding seawater and/or increased availability of bicarbonate in the boundary layers around its surface. Our results highlight the potential for pH-buffering materials to assist marine organisms in coping with the effects of changing ocean conditions, but further research is required to understand the generality and mechanism(s) driving the beneficial effects of concrete and to test pH-buffering materials in the field.

Using mating-type loci to improve taxonomy of the Tuber indicum complex, and discovery of a new species, T. longispinosum.

Black truffles that morphologically resemble Tuber indicum have been known to occur in Japan since 1979. Our previous studies showed that there are two phylotypes of these truffles, both of which fell into the T. indicum complex (hereinafter “Tuber sp. 6” and “Tuber sp. 7”). However, their taxonomic treatment is still unclear. In this study, we conducted morphological and phylogenetic analyses for a total of 52 specimens from Japan (16 Tuber sp. 6 and 13 Tuber sp. 7), China (10 T. himalayense and 8 T. indicum), and Taiwan (5 T. formosanum). We compared ascospore ornamentation, size, distribution of asci with average number of spores per ascus, spine size and shape of the Japanese specimens with their allied taxa. For phylogenetic analysis, we sequenced two mating loci (MAT1-1-1 and MAT1-2-1) and three commonly used loci (ITS, β-tubulin, and TEF1-α). Three distinct lineages were recognized by phylogenetic analyses based on the sequences of the two mating-related loci and three independent loci. The Tuber sp. 6 sequences clustered with those of T. himalayense and T. formosanum, and there was no clear difference in morphology among them. Tuber sp. 7 formed a distinct lineage in each phylogram. The specimens tended to have five-spored asci more frequently than other allied species and could be characterized as having ascospore ornamentation with longer spines and narrower spine bases. We therefore described Tuber sp. 7 as a new species (T. longispinosum), and treat Tuber sp. 6 and T. formosanum as synonyms of T. himalayense.

Unraveling Individual Differences In The HIV-1 Transgenic Rat: Therapeutic Efficacy Of Methylphenidate

Despite the heterogeneity of HIV-1 associated neurocognitive disorders (HAND), assignment of categorical diagnoses based on the level of impairment (e.g., Frascati criteria) obfuscates the well-acknowledged variability observed within the population of HIV-1+ individuals. The present study sought to elucidate the natural heterogeneity in adult HIV-1 transgenic (Tg) rats using three interrelated aims. First, heterogeneity of the HIV-1 transgene was examined using a pretest-posttest design to assess therapeutic efficacy of oral self-administration (OSA) of methylphenidate (MPH; 2.4 ± 0.2 mg/kg), targeting neurotransmitter alterations in HIV-1, on temporal processing. Approximately 42% of HIV-1 Tg animals displayed an improvement in temporal processing following OSA of MPH. Second, repeated OSA of MPH (22–27 days) altered dendritic spine morphology in layer II-III pyramidal neurons in the medial prefrontal cortex. HIV-1 Tg animals exhibited a population shift towards longer spines with decreased head diameter on lower order branches; a shift associated with temporal processing impairment. Third, in HIV-1 Tg animals, dendritic spine backbone length (µm) was associated with temporal processing impairment; a brain/behavior relationship not observed in control animals. Assessing the therapeutic efficacy of MPH revealed heterogeneity in the neural mechanisms underlying neurocognitive impairments, providing a key target for individualized therapeutic and diagnostic approaches for HAND.

A new species of Rhagovelia Mayr, 1865 (Hemiptera: Heteroptera: Veliidae) from Pará State, with an updated key to Brazilian species of the robusta group.

Rhagovelia brunae Magalhães & Moreira sp. nov., collected in the State of Pará, Brazil, is described, illustrated, and compared with congeners. The new species belongs to the robusta group and can be differentiated from others by the general color black, abdominal sternum VII with black denticles laterally, male hind trochanter with 1-4 subequal spines plus a longer spine, and male hind femur lacking a medium spine between the proximal and distal rows of spines. Additionally, an updated identification key to species of the robusta group occurring in Brazil is presented.

How predation shaped fish: the impact of fin spines on body form evolution across teleosts.

It is well known that predators can induce morphological changes in some fish: individuals exposed to predation cues increase body depth and the length of spines. We hypothesize that these structures may evolve synergistically, as together, these traits will further enlarge the body dimensions of the fish that gape-limited predators must overcome. We therefore expect that the orientation of the spines will predict which body dimension increases in the presence of predators. Using phylogenetic comparative methods, we tested this prediction on the macroevolutionary scale across 347 teleost families, which display considerable variation in fin spines, body depth and width. Consistent with our predictions, we demonstrate that fin spines on the vertical plane (dorsal and anal fins) are associated with a deeper-bodied optimum. Lineages with spines on the horizontal plane (pectoral fins) are associated with a wider-bodied optimum. Optimal body dimensions across lineages without spines paralleling the body dimension match the allometric expectation. Additionally, lineages with longer spines have deeper and wider body dimensions. This evolutionary relationship between fin spines and body dimensions across teleosts reveals functional synergy between these two traits and a potential macroevolutionary signature of predation on the evolutionary dynamics of body shape.

Ceradocus adangensis, a new species (Crustacea, Amphipoda, Maeridae) from coral reefs of the Andaman Sea

A new species of maerid Amphipoda, Ceradocus adangensis, collected from the coral reef at Adang Island in the Andaman Sea, is described. C. adangensis is characterized by its male large gnathopod 2 palm oblique with a subrectangular distomedial elevation with 5 robust setae, deeply cleft telson, telsonic lobes separated, each lobe with 4 apical robust setae and telsonic lobes not reaching halfway along the longest spine. The new species is compared with related species.

Comparison of first year growth among field, hatchery- and laboratory-raised juvenile red king crab, Paralithodes camtschaticus (Tilesius, 1815), in Alaska

In an effort to better understand juvenile growth in the first year and to determine potential effects of hatchery larval rearing, we compared growth of juvenile red king crab, Paralithodes camtschaticus (Tilesius, 1815), in the field and under laboratory-rearing conditions. Glaucothoe were obtained from the Alutiiq Pride Shellfish Hatchery and field; once molted to first stage juveniles, both sets were raised individually in the laboratory under ambient conditions (hereafter called hatchery/laboratory-reared and wild/laboratory-reared, respectively) and measured at each molt. Field-surveyed juveniles were observed and measured monthly in the intertidal in Juneau, AK, USA. Size, molt interval, cumulative molt interval, and molt increment did not differ significantly between hatchery/laboratory-reared and wild/laboratory-reared crab or between male and female crab over one year. Crab reached an average size ± SD of 13.6 ± 2.1 mm CL after 10-11 molts/year with 24% average molt increment at ambient temperatures. Carapace lengths of hatchery/laboratory-reared, wild/laboratory-reared, and field-surveyed juveniles were not significantly different in five of eight months from January through August, with small differences in January, February, and May, likely resulting from differences in hatch timing. Spine lengths differed from January through March but not from April through August. Spine lengths of hatchery/laboratory-reared crab were significantly larger than field-surveyed crab from January through March. Wild/laboratory-reared crab had significantly longer spine lengths than field-surveyed crab in February and March. In conclusion, growth did not differ significantly among juveniles reared in the laboratory and from the field.