1998. The Journal of Arachnology 26:296-302

LEG AUTOTOMY AND ITS POTENTIAL FITNESS COSTS FOR TWO SPECIES OF HARVESTMEN (ARACHNIDA, )

Cary Guffey' : Department of Biology, PO Box 42451, University of Southwestern Louisiana, Lafayette, Louisiana 70504 USA

ABSTRACT . Leg autotomy often confers immediate benefits on the losing its legs, such as escape from a predator, while costs are usually less obvious and accrue long after the leg is lost . I conducted a survey to determine the prevalence and characteristics of leg autotomy in two species of harvestmen, nigripes Weed 1892 and L. vitlalum Say 1821, from May-December 1996 at Chicot State Park, Evangeline Parish, Louisiana . Nearly half of all individuals found were missing at least one leg . There was no significant difference in the median number of legs between months for L. nigripes, but differences were found among several months for L. vittatum. Either of the second legs was most likely to be lost in both species . These results indicate that leg autotomy is common in harvestmen . Furthermore, these results suggest that the second legs are not as crucial to the survival of harvestmen as previously believed. Leg autotomy may result in a reduction of potential fitness for individuals, but harvestmen may choose to incur these costs rather than risk a catastrophic loss of fitness (e .g ., death) ; that is, leg autotomy may be a bet-hedging strategy for harvestmen .

Autotomy of appendages is widely known therefore, there are no costs associated with for a variety of animal groups, including mol- regeneration, such as allocation of nutrients to luscs (Edmunds 1966), crustaceans (Juanes & new tissue . However, harvestmen also are not Smith 1995), (e .g ., spiders : Forma- able to recover the benefits that they originally nowicz 1990 ; harvestmen : Kaestner 1968), in- had with the full complement of eight legs . sects (Carlberg 1994), echinoderms (e.g ., Thy- Because harvestmen do not regenerate their one briareus LeSueur 1824 : Smith & legs, when confronted with predators they Greenberg 1973), salamanders (Wake & Dres- should be under natural selection to weigh the ner 1967), and lizards (Arnold 1984) . The ef- benefits of leg autotomy against the future fect that autotomy has on the fitness of an in- costs associated with autotomy, such as sub- dividual depends on the sum of the benefits sequent encounters with predators, loss of mo- and costs of appendage loss . Benefits may be bility, loss of foraging ability, or loss of mat- immediate or nearly so and include distraction ing opportunities . of predators (Arnold 1984), escape from a The second pair of legs is the longest in predator's grasp (Arnold 1984), and escape Leiobunum (Kaestner 1968 ; Edgar 1990), and from traps (e .g ., spider webs) . Costs are these legs are believed to contain the main spread over a longer period of time and in- sensory organs of these (Comstock clude loss of mobility or balance, reduced 1920 ; Edgar 1963 ; Cloudsley-Thompson ability to escape subsequent encounters with 1968) . In one study, harvestmen that had lost predators, decrease in social status, divergence the second pair of legs were reported to be of energy resources to replacement of the lost more reluctant to move, eat, drink, or mate appendages, decrease in mating success, and (Sankey & Savory 1974) . Cloudsley-Thomp- even death in some instances (reviewed in Ed- son (1968) wrote that the loss of both of the munds 1974 ; Arnold 1984, 1988 ; Juanes & second pair of legs quickly results in death . Smith 1995) . Given the reported importance of the second Harvestmen autotomize their legs but do pair of legs, I predict that harvestmen should not regenerate them as either juveniles or be particularly reluctant to autotomize this adults (Comstock 1920 ; Kaestner 1968) ; pair compared to the other pairs . In general, three different life histories can ' Current address : Our Lady of the Lake University, be found in Opiliones (Todd 1949) . (1) Eggs 411 SW 24th St ., San Antonio, Texas 78207 USA . laid the previous autumn hatch in the spring .

296 GUFFEY--LEG AUTOTOMY IN HARVESTMEN 297

The animals mature over the summer and lay corded location, number of legs, which legs eggs in the autumn, then adults may or may were missing, and whether or not collected in- not die at the first frost (e.g., Leiobunum ni- dividuals were found in the copulatory posi- gripes Weed 1892) . This results in an overlap tion. Both species in this study are sexually of generations in some species (e.g., Phalan- dimorphic, but the characters used to identify gium opilio Linnaeus 1758 : Clingenpeel & the sexes of L. nigripes (size, color; pers. obs.) Edgar 1966) . (2) Eggs hatch in the autumn are not as reliable as that used for L. vittatum and the young overwinter . The young mature (size of pedipalps ; Davis 1935) . Any animals during the following summer, lay their eggs, for which the sex was uncertain were removed then die before the clutches hatch . Clingen- from comparisons based on sex . I released all peel & Edgar (1966) used populations of animals near the sites at which they were col- Leiobunum politum Weed 1889 and L. vitta- lected. A previous mark-recapture study in- tum Say 1821 from Michigan as examples, but dicated that <10% of marked animals were the latter species appears to follow pattern I caught at the site at which they were marked in south central Louisiana (pers . obs .). (3) As after 24 h and < I % were recaptured after two in the previous case, the eggs hatch in the au- weeks (unpubl . data); therefore, pseudorepli- tumn and the young overwinter. Eggs are laid cation due to resampling should have been the following autumn, but the adults do not negligible. die until after the eggs hatch, resulting in an Comparisons between months .-I used a overlap of generations (e .g., L. townsendi Kruskal-Wallis one-way ANOVA by rank Weed 1893 : Cokendolpher et al . 1993). Har- (Siegel & Castellan 1988) to determine if vestmen are ametabolous, and the young un- there was any significant difference for each dergo 5-8 molts before reaching adulthood species in the number of legs present among (Edgar 1971 ; Kaestner 1968) with the first months . When a significant difference was de- molt taking place within hours of hatching tected, I used a multiple comparisons test (Edgar 1971) . (Siegel & Castellan 1988) to locate significant Both L. vittatuin and L. nigripes were col- differences between months . These tests were lected throughout the year at Chicot State two-tailed and the test statistics were adjusted Park, Evangeline Parish, Louisiana ; but it was for ties with a = 0 .05 . common to find only adult L. vittalum from Comparisons of leg pairs .-I summed the late November to early January and to find number of times that either leg of a particular only juvenile L. nigripes from early January pair was autotomized and compared these ob- to mid-February. Leiobunum nigripes served values to an expected value obtained emerged 1--2 months earlier than L. vittatum. by assuming that each pair was equally likely In this study, I conducted field observations to lose a member. The probability (P) that ei- of L. nigripes and L. vittatum to determine the ther leg of any particular pair would be lost prevalence of leg autotomy in these species, was 0.25. This value was calculated as follows which legs are most likely to be autotomized, P(X,, or Xk) = P(X,) + P(X1,) _ % + /K = /K and what costs might be associated with leg = 0.25 autotomy. 1 predicted that : (1) the proportion of individuals missing legs should increase where X is any particular leg pair, L indicates with age, (2) the second legs should be the left, and R indicates right . This null hypothesis least likely to be autotomized, and (3) indi- was evaluated for both species with a Chi- viduals found mating should be more likely to square goodness of fit test (Freund & Simon have all eight legs than those individuals 1992) and compared to a = 0 .05. found alone . I compared the number of individuals miss- ing both legs of the second pair to an expected METHODS probability of 0 .036 (again assuming an equal Study animals.-I observed juveniles and likelihood that any leg would be autotomized) . adults of L. nigripes and L. vittatum at Chicot This probability was calculated as follows State Park, Evangeline Parish, Louisiana be- P(X) = P(X,) and P(X,) = P(X,)P(X2) _ tween May and December 1996 . Individuals (/) ('/7) = 0.036 were collected from cabins, vegetation, and 10.2 X 10.2 X 50.0 cm wooden posts . I re- where X is any particular leg pair. I used a

298 THE JOURNAL OF ARACHNOLOGY

0 .6 Leiobunum nigripes 0 .7 427 Males Females L . nigripes L . vittatum 167 0 .6 ze

0 .5 0 0 .5 0 61 0 .4 0 0 .3 0 .4 0 w 0 .2 s 7 0 0 .i 2 2 0 0 .3 223 0 .0 - a e4 4 5 6 7 8 4 5 6 7 8 0 2 Number of legs present a Leiobunum vittatum 0 .2 0 .7

43 71 0 .6 4

0 .5 0 .1 0q 17 „ 0 .4 0 131 92 0 0 .3 0 .0 W '' 0 .2 4 5 6 7 8 40 Number of legs present 0 .1 I z o Figure l .-The incidence of leg autotomy in two 0 .0 4 5 6 7 8 4 5 6 7 8 species of harvestmen from Evangeline Parish, Number of legs present Louisiana, May-December 1996 . The proportion of individuals with a given number of legs was not Figure 2 .-A comparison of leg number by spe- significantly different between the two species . The cies and sex . There was no significant difference in numbers above the bars indicate sample sizes . proportions between the sexes for either Leiobunum nigripes or Leiobununi vittatum. The dashed verti- cal line separates the data for males from that for females in each graph . The numbers above the bars one-tailed binomial test (Siegel & Castellan indicate sample sizes. 1988) to evaluate the null hypothesis that the observed values for the loss of the second pair kal & Rohlf 1995) . The test statistic was com- of legs came from a binomial distribution with pared to a = 0 .05 . P = 0.036. 1 compared the test results to a = 0 .05. RESULTS Comparisons of mating pairs with lone Nearly half of all harvestmen found were individuals .-I counted the number of legs of missing at least one leg (Fig. 1) . There was those individuals of L. vittatum found in the no significant difference between L. nigripes copulatory position and those found alone on and L. vittatum in the proportion of individ- 24 and 31 October 1996. Copulation in both uals at each level of leg loss (X2 = 5 .65, P = L. nigripes and L. vittatum occurs when the 0.226). Likewise, there was no significant dif- male grasps the female's prosoma with his ference between the sexes in the proportion of pedipalps and repeatedly attempts to insert his individuals missing a particular number of penis under the genital operculum of the fe- legs within either L. nigripes (Fig. 2A; X2 = male (L. nigripes : pers. obs. ; L. vittatum: Ed- 0.53, P = 0 .768) or L. vittaturn (Fig. 2B; X 2 gar 1971 ; Macias-Ordoiiez 1997) . I compared = 1 .77, P = 0.621). The ratio of males to the number of legs of those animals found females was 1 .3 :1 (n = 136) for L. nigripes alone to those found in the copulatory posi- and 1 .4:1 (n = 897) for L. vittatum. tion; but because of the small sample sizes of There was no significant difference in the those animals with seven or fewer legs, I median number of legs among months for L. pooled all of those animals and compared nigripes (Table 1 ; df = 7, KW = 10.07). A them to animals with eight legs in my statis- significant difference was detected among tical analyses . I tested the null hypothesis of months in the median number of legs for L. no significant difference with a G-test of in- vittatum (Table 2; (i= 7, KW = 43 .01) . A dependence with the Williams correction (So- multiple comparisons test indicated that those

GUFFEY--LEG AUTOTOMY IN HARVESTMEN 299

Table 1 .-Leg number for Leiobunum nigripes Table 2.-Leg number for Leiobunum vittatum by month . A Kruskal-Wallis one-way ANOVA by by month . A Kruskal-Wallis one-way ANOVA by rank, adjusted for ties, yielded P = 0 .186 . rank, adjusted for ties, yielded P < 0 .001 . Like su- perscripts indicate no significant difference in me- Month n Mean (+ SE) Median dians between those months as detected by a mul- tiple comparisons test . May 109 7.1 (0 .10) 7.0 June 42 7.0 (0 .16) 7.0 Month n Mean (+ SE) Median July 46 7.4 (0 .12) 8 .0 August 39 7.4 (0 .15) 8 .0 May 100 7.6 (0 .07) 8 .0^ September 31 7.5 (0 .17) 8 .0 June 31 7.4 (0 .14) 8 .0^B October 24 7 .2 (0 .23) 8.0 July 119 7.5 (0 .07) 8 .0^ November 21 7 .4 (0 .19) 8 .0 August 45 7.4 (0 .10) 8 .0^B December 4 7 .8 (0 .25) 8.0 September 173 7.4 (0 .06) 8 .0^ October 58 7.2 (0 .14) 8 .0^B November 102 7 .2 (0 .09) 7.5^B December 156 6.9 (0 .08) 7.OB animals found in December had significantly fewer legs than those in May, July, and Sep- tember (Table 2) . role in sensing the surrounding environment For both L. nigripes and L. vittatum, I de- of individuals of Leiobunum (Comstock 1920 ; termined that legs were not equally likely to Sankey & Savory 1974) . Therefore, I predict- be lost (Fig . 3 ; L. nigripes : = 19 .93, X2 P < ed that harvestmen are under pressure from 0 .001 ; L. vittatum : = 42 .06, 0.001) . A X2 P < natural selection to protect those legs . How- leg was most likely to be missing from the ever, the results presented here indicate that second pair in both species (Fig . 3) . The sec- when only one leg is autotomized, the lost ond pair of legs was missing significantly limb is most likely to be from the second pair more often than expected for both L. nigripes (n = 26, k = 6, P < 0 .001) and L . vittatum (n = 86, =6,P=0 .034). 0 .5 k L . nigripes L . vittatum I found no significant difference in leg number for those males of L. vittatum found in a copulatory posture (n = 21) compared to 0 .4 those found alone (Fig . 4A ; G = 0 .015, P = 0 .902) . Likewise, there was no significant dif- ference in leg number for those females found r 0 .3 in the copulatory position (n = 20) and those 0 found alone (Fig . 4B; = 3 .10, P = 0 .078) . X2 00 There was no significant difference between 0 a the sexes of L . vittatum in the numbers of an- w 0 .2 imals with eight legs found alone (G = 3 .006, P = 0.083) .

DISCUSSION 0 .1 Because Leiobunum is typically univoltine (Clingenpeel & Edgar 1966 ; Cokendolpher et al . 1993) and does not regenerate autotomized 0 .0 1st 2nd 3rd 4th legs, I predicted that the average number of Leg pair legs per individual would decrease with time . Figure 3 .-The proportion of each pair of legs Contrary to expectations, the median number 'represented in the sample of those harvestmen of legs did not decrease in L. nigripes over missing at least one leg . The observed numbers the course of the study period . However, were significantly different from the values expect- Leiobunum vittatum found in December had ed given an equal chance of autotomy for all legs . significantly fewer legs than those found in The expected proportion is represented by a solid May, July, and September. horizontal line across the middle of the graph . The The second pair of legs plays an important numbers above the bars indicate sample sizes .

100 THE JOURNAL OF ARACHNOLOGY

0 Males fore, intraspecific or intrasexual combat do not s appear to be significant causes of leg autoto- 0 my. If nutrition is responsible for a significant s degree of leg loss, then the average number 0 of legs present per animal should decrease s during juvenile stages (January-July) but should not change significantly after the final 0 mating alone molt (ca. July) . My data do not cover the ear- liest molts, but I found no significant differ- ences in leg number between the later instars and adults, suggesting that nutritional state is not the primary cause of loss of legs in older Females juveniles. 8 legs - 11 8 legs If the risk of predation is equal between species and between sexes within species, then this would explain why there is no sig- nificant difference in leg number between these groups . Furthermore, because the second legs are longer than any others in Leiobunum (Kaestner 1968 ; Edgar 1990) and these legs z are the first part of the harvestman to move 0 when individuals are disturbed (Comstock alone mating 1920; Sankey & Savory 1974), these legs are Figure 4.-A comparison of leg numbers of most likely to come into contact with preda- those individuals of Leiobunum vittatum found ei- tors or traps and thus to be autotomized . Spi- ther mating or alone on 24 and 31 October 1996 . vak & Politis (1989) found that the longest There was no significant difference in the number and most exposed limbs of crabs were the of animals found either mating or alone for males most likely limbs to be autotomized . If the or females . second legs are the most important sensory organs of harvestmen, then autotomy may re- of legs . Also, the second pair of legs is sig- sult in a substantial cost to these animals in nificantly more likely to be lost than expected terms of loss of sensory ability . if one assumes that all legs have an equal Though the data presented here indicate probability of being lost. that there was no significant difference in leg My final prediction was that significantly number between L. vittatum found mating and more individuals of L. vittatum found mating those found alone, I did not have enough in- would have all eight legs than those individ- dividuals missing two or more legs to make uals found alone . This would be expected if comparisons at specific levels of leg autotomy legs are important for finding mates or in in- (e.g., eight legs vs. six legs) . There may be a trasexual contests. I found no significant dif- cost in fitness due to reduced mating success ference in the proportions of individuals with as a result of leg autotomy, especially when eight legs found mating compared to those two or more legs are missing . Such costs may found alone for either sex . be caused by a reduced ability (1) to find Leg autotomy is common in L. nigripes and mates because of lessened mobility or dimin- L. vittatum. Leg loss may be caused by (1) ished sensory capacity, (2) to find oviposition intraspecific or intrasexual battles, (2) poor or mating sites, or (3) to prevail during in- nutrition resulting in loss of legs during molt- trasexual encounters . Mates and oviposition ing, or (3) different types of predation pres- sites are apparently identified only through di- sures such as direct attack or loss in webs . rect contact with the legs (Macias-Ordoiiez Males of L. vittatum fight over access to ovi- 1997). Therefore, leg autotomy has the poten- position sites by shoving one another with tial to impose a significant cost on the future their bodies, only rarely grasping one another fitness of both males and females of L. vitta- by the legs (Macias-Ordoiiez 1997) . There- tum. GUFFEY--LEG AUTOTOMY IN HARVESTMEN 301

Males of L. vittatum with more legs than ences would only be detectable after a certain their opponents win significantly more male- number of legs are lost, requiring a finer res- male contests when both males have equal ter- olution of the categories compared . ritorial status, but the contest winners do not It remains to be determined (1) if leg au- achieve increased mating success (Macias-Or- totomy at any level is costly to harvestmen donez 1997). Macias-Ordonez (1997) con- and, if it is costly, (2) at what point leg loss ducted his research at a site in which ovipo- becomes so costly that a harvestman would sition (and hence, mating) sites were not be just as well off risking a catastrophic fail- limited. Therefore, contest losers were soon ure of reproduction (e .g., because of death by able to find other mating sites . The outcome predation) . While the present study does not of contests, and thereby leg number, might be quantify the costs associated with leg autoto- more important in those areas in which ovi- my, it suggests that such costs exist and leads position sites and access to females are limited to an expectation that there is some level of or when male-male contests involve individ- leg autotomy at which harvestmen obtain a uals with unequal territorial status . I could not greater payoff for not losing any additional determine if the oviposition sites for the pop- legs. ulations in this study are limited . Bet-hedging strategies are those behaviors ACKNOWLEDGMENTS that decrease the expected fitness of an indi- Financial support for this research was pro- vidual but with the benefit of reducing the risk vided by a grant from the American Arach- of a total loss of fitness ; that is, lower poten- nological Society Fund for Graduate Student tial fitness is offset by a reduction in the vari- Research, Louisiana Board of Regents Doc- ance of fitness (Seger & Brockmann 1987). toral Fellowship grant LEQSF[1994-99]-GF- Leg autotomy may reduce an individual's ex- 29 to C . Guffey through R .G. Jaeger, grants pected fitness by decreasing its sensory ca- from The University of Southwestern Louisi- pabilities (unpubl . data). It is also possible that ana Graduate Student Organization, and a individual fitness may decrease as a result of grant from the Steuben Fund for Graduate autotomy due to reduced mobility or increased Student Research at The University of South- risk of capture during subsequent encounters western Louisiana . The staff and administra- with predators . Harvestmen that autotomize tion of Chicot State Park graciously allowed their legs presumably benefit by avoiding be- me to conduct research at the park . Construc- ing eaten by spiders or other predators . The tive advice was provided by H .J. Brockmann . interaction between the immediate benefits Field assistance was provided by T Guffey, obtained from leg autotomy and its later costs D. Guffey, and M . Guffey . J. Cokendolpher fits the model for a bet-hedging strategy (Se- helped with species identification . The manu- ger & Brockmann 1987) . script was improved by comments from R .G. To this point, I have considered only the Jaeger, R . Macias-Ordonez, and an anony- hypothesis that leg autotomy imposes a cost mous reviewer. on those harvestmen that lose legs . An alter- native hypothesis is that harvestmen have LITERATURE CITED enough legs such that loss of one or a few of Arnold, E.N. 1984. Evolutionary aspects of tail them does not cause any substantial reduction shedding in lizards and their relatives . J. Nat. in the expected fitness of an individual-in Hist., 18 :127-169. other words, harvestmen may have spare legs . Arnold, E.N. 1988. Caudal autotomy as a defense . Most of the data presented above show only Pp . 235-273, In Biology of the Reptilia, Vol . 16, the potential for a reduction in fitness . Within Ecology B (C . Gans & R. B. Huey, eds .). A.R. each sex, there was no significant difference Liss, New York. Carlberg, U . 1994. Cost of autotomy in the Phas- in the proportions of individuals found alone mida (lnsecta) . II. Species with high autotomy or mating . The spare-leg hypothesis would frequency. Zool. Anz., 232:41-49. lead to the prediction that when animals are Clingenpeel, L .W. & A.L. Edgar. 1966. Certain divided into groups with either all eight legs ecological aspects of Phalangium opilio (Arthro- present or those missing one or a few legs, as poda: Opiliones) . Pap. Michigan Acad . Sci. Arts reported in this study, there would be no sig- Lett., 51 :119-126. nificant differences detectable . Instead, differ- Cloudsley-Thompson, J .L. 1968. Spiders, Scorpi- 302 THE JOURNAL OF ARACHNOLOGY

ons, Centipedes and Mites. Pergamon Press, Ox- Kaestner, A . 1968 . Invertebrate Zoology, Vol . II : ford, United Kingdom. Relatives, , Myriapoda Cokendolpher, J .C., WP MacKay & M .H. Muma . (translated by H .W. Levi & L .R. Levi). Intersci- 1993 . Seasonal population phenology and habi- ence Publishers, New York . tat preferences of montane harvestmen (Arach- Macias-Ordbnez, R. 1997 . The mating system of nids: Opiliones) from southwestern New Mexi- Leiobunum vittatuin Say 1821 (Arachnida : Opi- co. Southwest . Nat., 38 :236-240 . liones : Palpatores) : resource defense polygyny in Comstock, J .H . 1920 . The Spider Book . Double- the striped harvestman . Ph .D. Dissertation, Le- day, Page & Co ., Garden City, New York . high University, Bethlehem, Pennsylvania . Davis, N .W. 1935 . A revision of the genus Leiob- Sankey, J .H .P. & T.H . Savory . 1974 . British Har- unum (Opiliones) of the United States . American vestmen. Academic Press, New York . Midl. Nat ., 15 :662-705 . Seger, J . & H.J . Brockmann . 1987 . What is bet- Edgar, A .L. 1963 . Proprioception in the legs of hedging? Oxford Surv. Evol . Biol ., 4 :182-211 . phalangids . Biol . Bull ., 124 :262-267 . Siegel, S . & N.J. Castellan, Jr. 1988 . Nonparamet- Edgar, A .L. 1971 . Studies on the biology and ecol- ric Statistics for the Behavioral Sciences, 2nd ed . ogy of Michigan Phalangida (Opiliones) . Misc. McGraw-Hill, Inc ., New York . Publ. Mus. Zoo . Univ. Michigan, 144:1-64 . Sokal, R .R . & EJ . Rohlf. 1995 . Biometry, 3d ed . Edgar, AL . 1990. Opiliones (Phalangida) . Pp. W.H. Freeman & Co., New York. 529-581, In Soil Biology Guide (D.L. Dindal, Smith, Jr., G .N. & M.J. Greenberg . 1973. Chemical ed.). John Wiley & Sons, New York . control of the evisceration process in Thvone bri- Edmunds, M . 1966 . Protective mechanisms in the areus . Biol . Bull ., 144 :421-436 . Eolidacea (Mollusca Nudibranchia) . J. Linn . Soc . Spivak, E .D. & M.A. Politis . 1989. High incidence (Zool .), 46 :27-7 1 . of limb autotomy in a crab population from a Edmunds, M. 1974. Defence in Animals. Longman coastal lagoon in the province of Buenos Aires, Group Limited, New York. Argentina . Canadian J . Zool ., 67 :1976-1985 . Formanowicz Jr., D .R. 1990 . The antipredator ef- Todd, V. 1949 . The habits and ecology of the Brit- ficacy of spider leg autotomy. Anim . Behav ., 40 : ish harvestmen (Arachnida, Opiliones), with spe- 400-401 . cial reference to those of the Oxford district . J. Freund, J .E. & G.A. Simon. 1992 . Modern Ele- Anim. Ecol ., 18 :209-229 . mentary Statistics, 8th ed . Prentice Hall, Engle- Wake, D .B. & I .G. Dresner. 1967 . Functional mor- wood Cliffs, New Jersey. phology and evolution of tail autotomy in sala- Juanes, E & L .D. Smith . 1995. The ecological con- manders . J . Morphol ., 122 :265-306 . sequences of limb damage and loss in decapod crustaceans : a review and prospectus . J. Exp. Manuscript received 1 September 1997, revised 1 Mar. Biol . Ecol ., 193 :197-223 . April 1998 .