Phragmites australis (common reed) has expanded in many wetland habitats. Its ability to exclude other plant species has led to both control and eradication programs. This study examined two control methods-herbicide application or a herbicide-burning combinationfor their efficacy and ability to restore plant biodiversity in non-tidal wetlands. Two Phragmites -dominated sites received the herbicide glyphosate. One of these sites was burned following herbicide application. Plant and soil macroinvertebrate abundance and diversity were evaluated pre-treatment and every year for four years post-treatment using belt transects. The growth of Phragmites propagules-seeds, rhizomes, and rooted shoots-was examined in the greenhouse and under bare, burned, or vegetated soil conditions. Both control programs greatly reduced Phragmites abundance and increased plant biodiversity. Plant re-growth was quicker on the herbicide-burn site, with presumably a more rapid return to wetland function. Re-growth at both sites depended upon a pre-existing, diverse soil seed bank. There were no directed changes in soil macroinvertebrate abundance or diversity and they appeared unaffected by changes in the plant community. Phrag-mites seeds survived only on bare soils, while buried rhizomes survived under all soil conditions. This suggests natural seeding of disturbed soils and inadvertent human planting of rhizomes as likely avenues for Phragmites colonization. Herbicide control, with or without burning, can reduce Phragmites abundance and increase plant biodiversity temporarily. These changes do not necessarily lead to a more diverse animal community. Moreover, unless Phragmites is eradicated and further human disturbance is prohibited, it will likely eventually re-establish dominance.

The Glandulocaudinae is a subfamily of neotropical characid fishes from Central and South America. A unifying feature of the subfamily is the caudal gland, found almost exclusively in males. The gland consists of tissue on the base of the caudal fin covered in part by hypertrophied scales. Scale movement as the caudal fin is flexed appears to facilitate the release of chemical compounds from the glandular tissue. We describe here a different structure, found in the gill cavity of mature males in 12 of 17 glandulocaudine genera examined. Termed a gill gland, it develops as a male secondary sex character and appears morphologically suited to release chemical signals. The gland forms by the growth of tissue over and around 4-13 anterior gill filaments on the first gill arch, forming chambers with ventral openings. Within the gland chambers, gill secondary lamellae usually shorten and may disappear. When secondary lamellae persist, simple columnar epithelial cells develop between them. In the absence of secondary lamellae, the gland chambers are lined with a simple cuboidal or columnar epithelium. Gland size and the degree of gill modification vary among species. Gill glands appear absent in five glandulocaudine genera, suggesting character reversals based on current phylogenetic hypotheses and systematic classification. Gill gland morphology suggests that this structure releases chemical compounds into the gill current. The presence of gill glands only in mature males suggests a function in reproduction and/or male aggression. Together with studies of the caudal gland, this research suggests that chemical signals may play important roles in glandulocaudine reproduction.

Abstract. Behavioral flexibility and behavioral regulation through courtship signals may both contribute to mating success. Blue crabs (Callinectes sapidus) form precopulatory pairs after courtship periods that are influenced by female and perhaps male urine-based chemical signals. In this study, male and female crabs were observed in 1.5-m circular outdoor pools for 45 min while the occurrence and sequence of courtship behaviors and pairing outcomes were recorded. These results were then compared with trials in which males or females were blindfolded; lateral antennule (outer flagellum) ablated; blindfolded and lateral antennule ablated; or had received nephropore blocks. The relative importance of visual and chemical sensory systems during blue crab courtship were then determined and urine and non-urine based chemical signals for both males and females were examined. Courtship behaviors varied considerably in occurrence and sequence; no measured behavior was necessary for pairing success. Male or female blindfolding had no effect on any measured behavior. Males and females required chemical information for normal courtship behaviors, yet blocking male or female urine release did not affect courtship behaviors. Males required chemical information to initiate pairing or to maintain stable pairs. Male urine release was necessary for stable pairing, suggesting that male urine signals may be involved in pair maintenance rather than pair formation. Females that could not receive chemical information paired faster and elicited fewer male agonistic behaviors. The results demonstrate a great variability and flexibility in blue crab courtship, with no evidence for stereotyped behavioral sequences. However, these behaviors appear regulated by urine-and nonurine-based redundant chemical signals emanating from both males and females. Although urine-based signals play roles in blue

In a 3.7-m Y-maze flume study of social odor-mediated behavior of mature lobsters (Homarus americanus), females preferred male- but not female-occupied shelters over empty shelters: they detected them from a distance and spent much time trying to enter. Males did not show distant detection and preference for female shelters but did spend much time trying to enter female but not male shelters once nearby. Sheltered resident males showed strong aggression toward visiting males but only mild aggression to visiting females; intermolt and premolt females could enter resident male shelters, cohabit for at least 7 h, receive mating attempts, and sometimes mate. Premolt females or females with sperm plugs resisted mating attempts. Visiting females released more than four times and males more than seven times as much urine during a shelter approach compared with an equal time in isolation. Females with or without urine release entered male-occupied shelters successfully, but mating attempts rarely occurred when female urine release was blocked. Female urine block resulted in greatly increased resident male aggression toward her, reaching the same levels elicited by visiting males with or without urine block. The results show that female urine signals reduce male aggression and facilitate mating.

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