scholarly journals Small size does not restrain frugivory and seed dispersal across the evolutionary radiation of Galápagos lava lizards

2018 ◽  
Vol 65 (4) ◽  
pp. 353-361 ◽  
Author(s):  
Sandra HervÍas-Parejo ◽  
Ruben Heleno ◽  
Beatriz Rumeu ◽  
Beatriz Guzmán ◽  
Pablo Vargas ◽  
...  
Keyword(s):  
Body Size ◽  
Structural Damage ◽  
Energy Content ◽  
Seedling Emergence ◽  
Fruit Size ◽  
Head Size ◽  
Emergence Time ◽  
Fruit Consumption ◽  
Fruit Abundance ◽  
Seed Dispersers

AbstractFrugivory in lizards is often assumed to be constrained by body size; only large individuals are considered capable of consuming fruits, with the potential of acting as seed dispersers. However, only one previous study has tested the correlation of frugivory with body and head size at an archipelago scale across closely related species. All nine lava lizards (Microlophus spp.) were studied on the eleven largest Galápagos islands from 2010 to 2016 to investigate whether frugivory is related to body and head size. We also tested whether fruit abundance influences fruit consumption and explored the effect of seed ingestion on seedling emergence time and percentage. Our results showed that across islands, lava lizards varied considerably in size (64–102 mm in mean snout–vent length) and level of frugivory (1–23%, i.e., percentage of droppings with seeds). However, level of frugivory was only weakly affected by size as fruit consumption was also common among small lizards. Lava lizards consumed fruits throughout the year and factors other than fruit abundance may be more important drivers of fruit selection (e.g., fruit size, energy content of pulp). From 2,530 droppings, 1,714 seeds of at least 61 plant species were identified, 76% of the species being native to the Galápagos. Most seeds (91%) showed no external structural damage. Seedling emergence time (44 versus 118 days) and percentage (20% versus 12%) were enhanced for lizard-ingested seeds compared to control (uningested) fruits. De-pulping by lizards (i.e., removal of pulp with potential germination inhibitors) might increase the chances that at least some seeds find suitable recruitment conditions. We concluded that lizards are important seed dispersers throughout the year and across the whole archipelago, regardless of body size.

scholarly journals Frugivore-fruit size relationships between palms and mammals reveal past and future defaunation impacts

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jun Ying Lim ◽  
Jens-Christian Svenning ◽  
Bastian Göldel ◽  
Søren Faurby ◽  
W. Daniel Kissling
Keyword(s):  
Body Size ◽  
Fruit Size ◽  
Global Scale ◽  
Occurrence Data ◽  
Evolutionary Changes ◽  
Palm Species ◽  
Seed Dispersers ◽  
Frugivore Assemblages ◽  
The Impact ◽  
Old World Tropics

Abstract Mammalian frugivores are critical seed dispersers, but many are under threat of extinction. Futhermore, the impact of past and future defaunation on plant assemblages has yet to be quantified at the global scale. Here, we integrate palm and mammalian frugivore trait and occurrence data and reveal a global positive relationship between fruit size and frugivore body size. Global variation in fruit size is better explained by present-day frugivore assemblages than by Late Pleistocene assemblages, suggesting ecological and evolutionary reorganization after end-Pleistocene extinctions, except in the Neotropics, where some large-fruited palm species may have outlived their main seed dispersers by thousands of years. Our simulations of frugivore extinction over the next 100 years suggest that the impact of defaunation will be highest in the Old World tropics, and an up to 4% assemblage-level decrease in fruit size would be required to maintain the global body size–fruit size relationship. Overall, our results suggest that while some palm species may be able to keep pace with future defaunation through evolutionary changes in fruit size, large-fruited species may be especially vulnerable to continued defaunation.

scholarly journals A MOISTURE CAPTURE SYSTEM FOR REDUCING SUPPLEMENTAL WATER REQUIREMENTS FOR CANTALOUPE PRODUCTION IN SEMI-ARID REGIONS.

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 587b-587
Author(s):  
David A. Bender ◽  
Frank J. Dainello
Keyword(s):  
Arid Regions ◽  
Seedling Emergence ◽  
Fruit Size ◽  
Growth And Yield ◽  
Emergence Time ◽  
Plastic Mulch ◽  
Supplemental Irrigation ◽  
Vine Growth ◽  
Soil Temperatures ◽  
Semi Arid

Trenched beds covered with plastic mulch was used to capture and retain precipitation for dryland cantaloupe production. Two trenches were formed in the fall in raised beds. Plastic mulch was laid over the beds and slitted at ca. 1 meter intervals over the trenches. Soil was placed over the slits, conforming the plastic to the shape of the trenches and channeling precipitation into the beds. Cantaloupes were seeded in the spring and grown with no supplemental irrigation. Planting moisture was significantly greater under the capture system than in unmulched beds. Seedling emergence time was reduced from 18 to 6 days and vine growth in the first 6 weeks was almost doubled. Total and marketable yields were doubled and fruit size significantly increased when water was limiting. Elevated soil temperatures under the mulch enhanced plant growth and yield even when moisture was not limiting. Combining a moisture capture system with supplemental irrigation could allow commercial production of cucurbit crops under limited water conditions in semi-arid areas.

scholarly journals Effects of Sand Burial Depth on Xanthium Spinosum Seed Germination and Seedling Growth

2021 ◽  
Author(s):  
yuanyuan Tao ◽  
Tian-cui Sang ◽  
Jun-jie Yan ◽  
Yun-xia Hu ◽  
Yu Zhao ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seedling Growth ◽  
Seedling Emergence ◽  
Soil Layer ◽  
Burial Depth ◽  
Seedling Height ◽  
Emergence Time ◽  
Deep Soil ◽  
Sand Burial ◽  
Emergence Rate

Abstract different sand burial depths on seed germination, seedling emergence, growth and biomass allocation were studied to provide a scientific basis for further control of X. spinosum. Six sand burial depths (1, 2, 3, 5, 7 and 9 cm) were established to explore the response of X. spinosum seed germination and seedling growth to sand burial. The first emergence time, peak emergence time, emergence rate, seedling growth height, biomass and biomass distribution of X. spinosum seeds had significant effects at different sand burial depths (P < 0.05). The X. spinosum seeds had the highest emergence rate (71.5%) at 1 cm sand burial and the maximum seedling height (7.1 cm). As sand burial depth increased, the emergence rate and seedling height gradually decreased, and the emergence rate (12.25%) and seedling height (2.9 cm) were lowest at 9 cm sand burial. The root length at 9 cm depth (13.6 cm) was significantly higher than that at other sand depths (P < 0.05). The sand burial depth affected the biomass accumulation and distribution of X. spinosum. As sand burial depth increased, the root biomass and rhizome ratio increased, and the most deeply buried seedlings allocated more biomass for root growth. The optimal sand burial depth for seed germination and seedling growth of X. spinosum was 1–3 cm, and high burial depth (5–9 cm) was not conducive to the germination and growth of X. spinosum seedlings. For prevention and control of X. spinosum, we suggest deeply ploughing crops before sowing to ensure X. spinosum seeds are ploughed into a deep soil layer.

scholarly journals Convergence in reduced body size, head size, and blood glucose in three island reptiles

2018 ◽  
Vol 8 (12) ◽  
pp. 6169-6182 ◽  
Author(s):  
Amanda M. Sparkman ◽  
Amanda D. Clark ◽  
Lilly J. Brummett ◽  
Kenneth R. Chism ◽  
Lucia L. Combrink ◽  
...  
Keyword(s):  
Body Size ◽  
Blood Glucose ◽  
Head Size ◽  
Reduced Body

Physiological Potential Evaluation of Myracrodruon urundeuva Stored Diaspores

2018 ◽  
Vol 10 (9) ◽  
pp. 125
Author(s):  
Vanessa Renata de Sousa Barboza ◽  
Monalisa Alves Diniz da Silva ◽  
Luan Danilo Ferreira de Andrade Melo ◽  
Edilma Pereira Gonçalves ◽  
Jeandson Silva Viana
Keyword(s):  
Pearson Correlation ◽  
Seedling Emergence ◽  
Emergence Time ◽  
Quantitative Factor ◽  
Pearson Correlation Test ◽  
Rapid Tests ◽  
Potential Evaluation ◽  
The Individual ◽  
And Storage ◽  
Test Individual

The conservation of seeds in an appropriate location combined with the utilization of rapid tests for monitoring the physiological aspects is essential for quality seedlings. Thus, the study aimed to evaluate the behavior of Myracrodruon urundeuva diaspore under different periods and storage environments, and verify the testing of individual exudate pH in the physiological monitoring. The experimental design was completely randomized, factorial 2 × 8 (8 periods of storage and 2 storage environments) with four replications of 25 diaspores, using the Tukey test at 5% probability for average comparisons. After analysis of variance, it was performed regression analysis for the quantitative factor and simple Pearson correlation test. The variables analyzed were moisture content, seedling emergence (E) emergence velocity index (IVE), mean emergence time (TME) and the pH of the individual exudate. The results of E, IVE, TME tests indicated that the Myracrodruon urundeuva diaspores could be stored for ten months in room fridge, with low vigor loss. The pH test individual exudate showed lower estimates of simple Pearson correlation with the emergence test, not monitoring the physiological potential of Myracrodruon urundeuva diaspores.       

Factors driving sexual dimorphism and colour variability in the Achala Copper Lizard (Pristidactylus achalensis), an endemic species to the highland mountains in central Argentina

2020 ◽  
Vol 98 (6) ◽  
pp. 377-389
Author(s):  
S. Naretto ◽  
M. Chiaraviglio
Keyword(s):  
Sex Differences ◽  
Spatial Distribution ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Endemic Species ◽  
Morphological Changes ◽  
Head Size ◽  
Head Width ◽  
Temporal And Spatial Distribution ◽  
Central Argentina

The intensity of mating competition varies according to the temporal and spatial distribution of individuals. Measuring sexual dimorphism over time and interpreting the association between individuals is therefore important if we aim to understand how sexual traits are influenced. We examined sex differences in the Achala Copper Lizard (Pristidactylus achalensis (Gallardo, 1964)), an endemic species from the highest part of mountains of central Argentina. Over 4 years, we explored sex-specific variation in body size, head size, interlimb length, and body colouration. Furthermore, we evaluated how these traits varied temporally, and we also explored whether the spatial distribution of individuals is explained by variation in these traits. We found that P. achalensis is a species with sexual dimorphism in multiple characters, including body size, head size, and colouration. Interestingly, some traits related to mating, such as head width, show a temporal variability in both sexes, whereas other traits, such as colouration, varies seasonally only in males. Our results underline the intriguing possibility of seasonal morphological changes related to mating, and more broadly that sex differences are influenced by sexual selection pressures mediated by temporal variation in mate competition.

Body size and trophic divergence of two large sympatric elapid snakes (Notechis scutatus and Austrelaps superbus) (Serpentes:Elapidae) in Tasmania

2012 ◽  
Vol 60 (3) ◽  
pp. 159 ◽  
Author(s):  
S. Fearn ◽  
J. Dowde ◽  
D. F. Trembath
Keyword(s):  
Body Size ◽  
High Frequency ◽  
Field Data ◽  
Trophic Ecology ◽  
Competitive Exclusion ◽  
Head Size ◽  
Large Prey ◽  
Potential Prey ◽  
Island State ◽  
Species Being

Tiger snakes (Notechis scutatus) and lowland copperheads (Austrelaps superbus) are both large viviparous elapid snakes confined to the cooler, mesic regions of southern Australia. In spite of both species being common and widespread in the island state of Tasmania, no quantified studies on the trophic ecology of these two snakes from the main island has been published. During a two-year period we collected field data from 127 adult A. superbus and 74 adult N. scutatus from throughout eastern Tasmania. For both species, males were larger than females with respect to all measured parameters, including mass and head size. Reproduction in females was strongly seasonal and clutch size was not related to maternal body size. N. scutatus has a larger head than A. superbus and consequently ingests both small and large prey. N. scutatus in our study displayed the most catholic diet of any Australian elapid studied to date and consumed mammals (possum, bandicoot, antechinus, rats, mice), birds (fairy wrens), fish (eel, trout) and frogs. A. superbus shows a more specialist diet of large volumes of predominately ectothermic prey (frogs, lizards, snakes) even at maximal sizes and was more likely to contain ingested prey than specimens of N. scutatus. Distinctive rodent bite scars were common on N. scutatus but rare on A. superbus. The high frequency of rodent bite scars on N. scutatus further supports our findings of a primarily endothermic diet for mature specimens. We suggest that significant differences in head size, and hence diet, as well as a taxonomically diverse suite of potential prey in Tasmania allow both these large snakes to coexist in sympatry and avoid interspecific competitive exclusion.

Heads or tails? Sexual dimorphism in helodermatid lizards

2007 ◽  
Vol 85 (1) ◽  
pp. 92-98 ◽  
Author(s):  
C.M. Gienger ◽  
Daniel D. Beck
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Morphological Traits ◽  
Tail Length ◽  
Repeated Sequences ◽  
Analysis Of Covariance ◽  
Head Size ◽  
Heloderma Suspectum

We tested the hypothesis that helodermatid lizards (Gila monsters, Heloderma suspectum Cope, 1869, and beaded lizards, H. horridum (Wiegmann, 1829)) show sexual dimorphism in morphological traits related to male–male agonistic behaviors. Male–male combat in helodermatid lizards involves repeated sequences of ritualized grappling. Male Gila monsters use their heads in attempts to gain or maintain a superior position during repeated combat bouts that may last for hours. Pairs of fighting male beaded lizards form spectacular body arches, with abdomens adpressed and snouts, forelimbs, and tail tips contacting the ground. We measured body size, head size, and tail length in 208 preserved H. suspectum, and body size and tail length (but not head size) in 79 live H. horridum, then tested for sexual dimorphism using analysis of covariance. Male Gila monsters had proportionately larger heads than females but did not differ in tail length or body size. Male beaded lizards had proportionately longer tails than females and were larger in body size only when the largest individuals were included in the analysis. Differences in head dimensions (in H. suspectum) and tail length (in H. horridum) are likely the result of sexual selection acting through male–male agonistic behaviors in this unique lizard taxon.

The manifestation and significance of sexual dimorphism in anguid lizards: a case study of Barisia monticola

1989 ◽  
Vol 67 (1) ◽  
pp. 68-72 ◽  
Author(s):  
James L. Vial ◽  
James R. Stewart
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Reproductive Behavior ◽  
Reproductive Potential ◽  
Head Size ◽  
Adult Males ◽  
Allometric Growth ◽  
Natural And Sexual Selection ◽  
Dimorphic Expression

The dimorphic expression of body size, body – head size relationships, and chromatic characters among anguid lizards is reviewed. These characteristics are quantitatively examined in a population of Barisia monticola. No sexual differences are found in body size. Head size is positively correlated with body size; however, allometric growth rates in head size are significantly greater in adult males than in females or juveniles. Adult males also differ significantly in eight of nine chromatic characters, the most pronounced being the presence of light dorsal scale markings. These differences are explored in the context of both natural and sexual selection. We hypothesize that the absence of dimorphism in overall body size is the result of natural selection operating to maximize female reproductive potential. In contrast, we predict that dimorphism expressed in body – head size relationships and dichromatism are consequences of sexual selection relating to agonistic and reproductive behavior of males.

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