ALBERT

Description: Alkaloid transport and storage are reviewed, with emphasis on problems associated with presence of toxic chemicals in living plants. Many patterns in the physiology of alkaloids and other defense compounds are shaped by the twin requirements that these compounds must be inactive in the plant and yet active in the presence of herbivores. The distribution of alkaloids in the plant and changes in distribution during the plant's life are also reviewed. Within individual plants, alkaloids are generally concentrated in those parts upon which herbivore attack would have the greatest effect on the plant's fitness. The relative defense requirements of different parts, based on their contribution to fitness and their vulnerability to herbivores, shift during the plant's life. These shifts are mirrored by corresponding shifts in alkaloid concentration. Ovules, seeds, and immature fruits are often the sites of highest alkaloid concentration. Allocation of defensive chemicals between mature and immature foliage should follow different patterns in trees and in herbs. In trees, the "phenological protection" given to synchronously produced flushes of new leaves and the need for protection of mature leaves until a new flush of young leaves can be produced have selected for greater toxin accumulation in mature leaves. In herbs, young leaves lack both mechanical and phenological defense, so there is strong selection for providing them with chemical defenses.

Description: 1. Ten species of prosobranch gastropod veligers collected from the open waters of the North Atlantic Ocean have been identified by comparison of their larval shells with the protoconchs of identifiable juvenile or adult museum specimens. The larvae described are those of Cymatium parthenopeum (von Salis), Cymatium nicobaricum (Röding), and Charonia variegata (Lamarck) belonging to the family Cymatiidae; Tonna galea (Linné) and Tonna maculosa (Dillwyn) belonging to the family Tonnidae; Phalium granulatum (Born) belonging to the family Cassidae; Thais haemastoma (Linné), a muricid; Philippia krebsii (Mörch), an architectonicidae; Smaragdia viridis (Linné), a neritid; and Pedicularia sicula Swainson belonging to the family Ovulidae. 2. The geographical distribution of the veligers of these ten gastropod species has been determined in the North and tropical Atlantic from approximately eight hundred and fifty plankton tows. The relationship between the North and Equatorial Atlantic circulation and the dispersal of gastropod veliger larvae can be seen from these data (Figs. 5-12). Charonia variegata, Philippia krebsii, and Pedicularia sicula were found in all three trans-Atlantic currents sampled, namely, the eastwardly moving North Atlantic Drift and the westwardly flowing North and South Equatorial Current. Cymatium parthenopeum and Tonna galea were found throughout the North Atlantic gyre, but only from scattered records in the South Equatorial Current. Phalium granulatum and Thais haemastoma were found in the North Atlantic Drift and South Equatorial Current. These seven species are regularly dispersed in either direction across the North Atlantic barrier. Smaragdia viridis was found in the western half of the North Atlantic Drift and in the eastern half of the South Equatorial Current; it is probably less frequently transported across the Atlantic. Cymatium nicobaricum veligers were found only once in mid-ocean in the North Atlantic Drift; all other records were restricted to the tropical and warm temperate Western Atlantic. Tonna maculosa veligers were found only in the Gulf Stream. The adults of all ten species are amphi-Atlantic in their geographical distribution and occur in the tropical and warm-temperate shelf waters. Adults of Cymatium nicobaricum and Tonna maculosa, however, are known from only a few records in the eastern tropical Atlantic. 3. The duration of pelagic larval development has been estimated for the same ten species of gastropods. Six species, Charonia variegata, Cymatium parthenopeum, Cymatium nicobaricum, Tonna galea, Tonna maculosa, and Phalium granulatum have a period of pelagic development of over three months. Pedicularia sicula and Smaragdia viridis can probably reach the settling state in less than two months. It is possible that the latter four forms have settling responses and can delay metamorphosis. A comparison between the duration of larval development and the velocity of the North and tropical Atlantic surface currents shows that transoceanic dispersal of the first six mentioned species is possible even without a delay in settlement. 4. The frequency of long-distance dispersal across ocean basins is chiefly dependent upon (a) the drift coefficient, that is, the probability that larvae will be carried off-shore into the major ocean surface currents rather than retained in the coastal waters of the parent population, and (b) the size of the parent population from which the larvae originate. There may be considerable variation in the frequency of long-distance dispersal related to larval mortality. 5. The lower limits of sensitivity obtained by using a conventional plankton net are such that it is possible for trans-oceanic dispersal to occur and yet go completely unnoticed. The concentration of only one larva per tow reoccurring at each station along a transect across the Atlantic may represent a significant amount of trans-oceanic dispersal. 6. If pelagic larvae are important in maintaining genetic continuity, then the degree of morphological differentiation between eastern and western Atlantic populations of gastropod species having amphi-Atlantic distributions would be expected to bear an inverse relationship to the frequency with which the veliger larvae of these species were found in the plankton of the open sea. The evidence from the gastropod species considered here seems to support this hypothesis (Table V).

Description: 1. This paper describes the population size structure, inferred age, growth, reproduction and longevity of the common Atlantic Coast squid, Loligo pealei. 2. The sampling includes records of size (dorsal mantle length), sex and sexual maturity of 15,132 squid taken from 1967-1970. Nearly half of these were collected offshore between Cape Hatteras and Georges Bank in the late winters of 1967 and 1968. The remainder, including planktonic, young-of-the-year squid were trawled in the vicinity of Woods Hole, Massachusetts between May and November of all three years. 3. Size classes were identified and weighted through the use of size frequency analysis and arrayed to provide an empirical growth model. Mean sizes of individuals appeared to increase smoothly to 16 and 18 cm at one year and 27 and 32 cm at two years for females and males, respectively. 4. Two broods arise each year, a ubiquitous July brood (probably delayed north of Cape Cod) and a November brood which probably originates in the southern mid-Atlantic Bight. Sexual maturity and breeding have not been observed at less than one year of age; at Woods Hole these features occur at different ages and slightly different dates for the two broods. Competition for females may postpone the breeding of some males and exaggerate the population sexual dimorphism. 5. The stock is basically annual, though a significant proportion of the squid hatching near Woods Hole appear to be the product of two year olds. A breeeding induced mortality is consistent with the growth scheme for both sexes. This mechanism is evoked to explain the dynamics of age structure and sexual maturity during the inshore season. 6. Maximum longevity is understood tentatively to be 36 months for males (more frequently 20-24 months) and months for females. Sex ratios were consistently close to 1:1 though not necessarily balanced in older age groups. 7. The proposed growth scheme provides an hypothesis for latitudinal variations in the stock of L. pealei. 8. The results are compared with Verrill's influential treatment of the species and found to differ principally in the interpretation of data. The proposed growth scheme appears to be applicable to published data for the European squid, L. vulgaris. and is contrasted with records from other loliginid squid.