Pre-dispersal seed predation by the weevils Trichapion rostrum and Tychius sordidus limits reproductive output of Baptisia alba (Fabaceae)

Botany ◽  
2017 ◽  
Vol 95 (8) ◽  
pp. 809-817 ◽  
Author(s):  
Ashley M. Hembrough ◽  
Victoria A. Borowicz

Baptisia alba (L.) Vent., an herbaceous, perennial legume, produces more flowers than will mature into pods. Single-year experiments on two reconstructed prairies tested the hypothesis that reproductive potential of B. alba depends on nutrients, but pollen limitation and pre-dispersal seed predation by weevils reduce final production. Ramets were assigned one of four treatments that were combinations of fertilizer (none/70 g fertilizer twice) and insect barrier (none/application of Tanglefoot). Within inflorescences, flowers were naturally pollinated or supplemented with pollen. Fertilizer produced no effects, suggesting that B. alba are unresponsive within a season to nutrient supplementation. Pollen supplementation increased pod initiation at the two sites by 6.7% and 2.3%, respectively, but did not affect the proportion of initiated pods that matured or seed number within pods. Where Tychius sordidus occurred, only 67 pods matured on 19 ramets and only four seeds survived. Where only Trichapion rostrum was present, insect barrier increased pod maturation almost three-fold, but did not affect seed number within pods. Barrier treatment increased the reproductive output of entire ramets by increasing seed production, from 3.6 seeds·ramet−1 to 60.5 seeds·ramet−1. Prairie restoration frequently uses fruit collected from other populations. Managers should be careful to avoid the unintended introduction of voracious seed predators.

2003 ◽  
Vol 81 (1) ◽  
pp. 24-27 ◽  
Author(s):  
José L Vesprini ◽  
Leonardo Galetto ◽  
Gabriel Bernardello

Dyckia floribunda is a perennial herb from the Argentinian Chaco with extrafloral nectaries. Ants visited these nectaries while patrolling inflorescences and infructescences. We anticipated that ants attracted to extrafloral nectaries might protect the reproductive organs, increasing plant reproductive output. To evaluate the possibility of mutualism between D. floribunda and ant visitors, we determined whether ant-accessible plants showed a higher seed production than ant-excluded plants. Experimental fieldwork suggested a decrease in fruit set of ant-excluded plants compared with ant-accessible plants but the seed number per fruit was not affected by ant exclusion. Thus, total seed number per plant was highly reduced in treated spikes. Analyses of covariance confirmed these trends, indicating that total seed production per plant was strongly affected by ant exclusion. This study marks the first experimental report of this mutualistic association in Bromeliaceae.Key words: ant–plant interaction, Bromeliaceae, Chaco, Dyckia floribunda, fruit set, seed set, mutualism.


Ecology ◽  
1995 ◽  
Vol 76 (2) ◽  
pp. 652-656 ◽  
Author(s):  
Johan Ehrlen ◽  
Ove Eriksson

1976 ◽  
Vol 27 (2) ◽  
pp. 217
Author(s):  
GJ Burch ◽  
P Andrews

Yarloop is a waterlogging-tolerant cultivar of Trifolium subterraneum subsp. yanninicum; it is highly oestrogenic. It is known to be a strong competitor and is widely grown in south-western Australia. Three new low-oestrogenic, waterlogging-tolerant genotypes of subsp. yanninicum were grown in monoculture, and in binary mixture in competition with cv. Yarloop, in large boxes in a glasshouse. Of the three, Y111 and Y136 gave satisfactory growth relative to Yarloop, and exhibited similar flowering and seed production; cv. Larisa, a late-maturing type, performed well until flowering and had a lower seed number than Yarloop. A second experiment examined the effects of defoliation during the vegetative phase on the relative performance of cv. Yarloop and cv. Larisa growing in mixtures of varying proportions. Two overall densities were used. The dominance of Yarloop over Larisa in uncut swards, due to its more vigorous growth habit, was nullified by regular cutting. The agronomic implications of the results are discussed.


1992 ◽  
Vol 79 (3) ◽  
pp. 288-293 ◽  
Author(s):  
Mark D. Bertness ◽  
Scott W. Shumway

Weed Science ◽  
1990 ◽  
Vol 38 (4-5) ◽  
pp. 374-378 ◽  
Author(s):  
Jill Schroeder ◽  
Clyde C. Dowler ◽  
James R. Stansell

The effect of soil matric potential from −0.02 to <–1.5 MPa on Texas panicum growth in drainage lysimeters covered by an automatic rainfall shelter was measured in 1984, 1985, and 1986. Rate of tiller production was faster for plants established in April than June in 1984 and 1985, but not 1986. In 1985 and 1986, dry weight was greater, but total seed production was less for plants established in April than June. Irrigation when the soil matric potential was −0.02, −0.075, or −1.5 MPa did not affect rate of tiller production in 1984. Irrigation when the soil matric potential was −1.5 MPa decreased dry weight of plants but increased seed number per panicle compared to irrigation when the soil matric potential was −0.02 MPa in 1985 and 1986. Plants grown in lysimeters irrigated at soil matric potential <–1.5 MPa in 1985 and 1986 did not wilt at 8:00 a.m.; therefore, they were not watered after establishment. These nonirrigated plants averaged 0.9 and 0.4 kg dry weight and produced 92 200 and 16 100 seeds in 1985 and 1986, respectively.


1993 ◽  
Vol 50 (1) ◽  
pp. 20-28 ◽  
Author(s):  
Andrew R. Lewis ◽  
J. Howard Choat

Reproductive biology of the tropical sepioid cephalopod Idiosepius pygmaeus was investigated in wild specimens and in individuals maintained in aquaria through the adult life span. This species produced multiple egg batches over 80% of the observable adult weight range, indicating a coordination of reproductive and somatic growth. Reproductive output was consistent within, but variable between, individuals. Oocyte synthesis and maturation occur continuously after sexual maturation has been reached. Senescence and death are not related to an exhaustion of reproductive potential. On average, captive female I. pygmaeus with access to unlimited food produced 640 eggs in 11 batches over 18 d. When reproductive output was expressed as a ratio of dry female body weight, on average, specimens had incorporated five times their body weight into eggs and egg coatings. Under food stress, captive specimens laid fewer eggs but maintained egg size and periodicity of egg laying. Food stress had no effect on either laying duration or weight at death. This study provides further evidence that terminal spawning modes are not ubiquitous amongst cephalopods.


2008 ◽  
Vol 99 (3) ◽  
pp. 245-251 ◽  
Author(s):  
L.L. Stelinski ◽  
L.J. Gut

AbstractThe effect of delayed mating on reproductive potential, longevity and oviposition period of female redbanded leafroller,Argyrotaenia velutinana(Walker) and Pandemis leafroller,Pandemis pyrusanaKearfott, was investigated in the laboratory. Virgin female or male moths of each species were held for 1, 2, 4, 6 or 10 days prior to pairing with one-day-old virgin conspecifics of the opposite sex. In addition, reproductive potential was assessed when both sexes of each species were aged for those periods prior to pairing. The expected reproduction of femaleA. velutinanawas reduced by 34, 53, 71 and 81% for 2, 4, 6 and 10-day delays in female mating, respectively. ForP. pyrusana, expected reproduction was reduced by 47, 74, 85 and 93% for 2, 4, 6 and 10-day delays in female mating, respectively. Increasing male age at mating in both species had a lesser effect on female reproductive output compared with increasing female age at mating. As maleA. velutinanaage at mating increased, the expected reproduction of femaleA. velutinanawas reduced by 15, 45, 54 and 70% for 2, 4, 6 and 10-day delays, respectively. Comparing maleP. pyrusanaof various ages at mating, expected reproduction was reduced by 14, 42, 64 and 79% for 2, 4, 6 and 10-day delays in mating, respectively. The decrease in female reproduction when both sexes were aged prior to mating was higher than when either sex alone was aged prior to pairing with a one-day-old virgin of the opposite sex. The expected reproduction of femaleA. velutinanawas reduced by 60, 83, 96 and 98% for 2, 4, 6 and 10-day delays in mating of both sexes, respectively. Only 7.5% of female eggs hatched when both sexes ofA. velutinanawere aged ten days prior to mating. When simultaneously aging both sexes ofP. pyrusanaprior to mating, expected reproduction was reduced by 71, 93, 96 and 99% for 2, 4, 6 and 10-day delays in mating, respectively. NoP. pyrusanaeggs hatched after a ten-day delay of mating for both sexes. For both species, female longevity increased and duration of oviposition period decreased with increasing female age at mating. Our results demonstrate that delayed mating in both females and males negatively affects female reproductive output in both species and that simultaneous aging of both sexes prior to mating has a greater effect than aging either sex alone. Our results suggest that laboratory studies that have paired aged females or aged males with conspecifics of optimal reproductive maturity have likely underestimated the effects of delayed mating on reproductive output.


1979 ◽  
Vol 9 (3) ◽  
pp. 327-335
Author(s):  
Donald B. Zobel

In 3 years of seed collection throughout the range of Chamaecyparislawsoniana (A. Murr.) Parl., 30 seed crops varied from 20 000 to 4 600 000 seeds per hectare. The overall mean was 829 000 seeds per hectare per year. Annual production per square metre of basal area (BA) varied from 600 to 185 000. Only 6 of 30 seed crops exceeded 50 000 seeds/m2 BA per year but these were produced by the youngest (65 year old) and oldest (450 + year old) stands and throughout the environmental range of the species. Of other seed crops, 11 had 10 000–50 000 seeds/m2 BA per year and 13 had fewer than 10 000 seeds/m2 BA per year. Year-to-year variation had a local, not regional, pattern. An open-forest community produced more seed per square metre of basal area than a denser one at two mixed evergreen zone sites. Seedfall peaked from October to November, with a smaller spring peak, but some seeds fell throughout the year. Most sites differed little in the timing of peaks. Germination of trapped seed from seven sites in 1 year was 11–44% and showed no correlation with crop size. Other species in this genus produce many more seeds per hectare than C. lawsoniana but there is no evidence that seed production limits reproductive potential of this species. In mixed forests, C. lawsoniana and especially Tsugaheterophylla (Raf.) Sarg. were over represented in the seedfall (compared with their basal area), whereas Pseudotsugamenziesli (Mirb.) Franco and Abiesconcolor (Gordon and Glend.) Lindl. ex Hildebr. produced less than their share.


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