Multiple visits to the same plant of a dioecious species
can increase the pollen load that has to be transported to other plants sometimes a long distance away.
Male-specific DNA in the dioecious species
Atriplex garrettii (Chenopodiaceae).
However, even a stock exhibiting the reproductive sucess rule has dynamics that are distinctly different from those of a dioecious species
because a change in the size distribution of the population due to size-selective fishing is predicted to have a large effect on the productivity and sex ratio of the protogynous population.
[c] The New York Botanical Garden 2011 Table 1 A Family Level Comparison Between the Number and Type of Dioecious Species
that have been Studied and those that Exist All dioecy Studied P=0.05 Distribution Tropical 145 15 Df=1 (130.6) (29.4) c.v=3.84 Temperate 77 35 X^2=20.98 (91.4) (20.6) Life form Tree 85 38 Df=2 (96.9) (26.1) c.v=5.99 Herb 70 20 X^2 =16.16 (70.9) (19.1) Shrub 98 10 (85.1) (22.9) Pollination Abiotic 53 21 Df=1 (62.1) (11.9) c.v=3.84 Biotic 124 13 X^2=12.76 (114.9) (22.1) Table 2 Evidence for Differential Resource Allocation to Reproduction Between the Sexes.
warwickii is larger than that of the dioecious species
Scalpellum stearnsii, where 69% of females had no neighbors (Ozaki et al., 2008).
The bivalves Tagelus plebeius (Lightfoot, 1786) (Psammobiidae) and Iphigenia brasiliana (Lamarck, 1818) (Donacidae) are dioecious species
. The stout razor clam T.
Hermaphroditism among dioecious Tagelus plebeius (Lightfoot, 1786) (Mollusca, Psammobiidae) and Iphigenia brasiliana (Lamarck, 1818) (Mollusca, Donacidae) on the Cachoeira River Estuary, Ilheus, Bahia, Brazil/Hermafroditismo nos moluscos dioicos Tagelus plebeius (Lightfoot, 1786) (Mollusca, Psammobiidae) e Iphigenia brasiliana (Lamarck, 1818) (Mollusca, Donacidae) na regiao estuarina do Rio Cachoeira, Ilheus, Bahia, Brasil
This is a minimum estimate of the number of transitions in mating systems in the family: we based our inferences on experimental reports for some species, anecdotal reports for others, and certain assumptions (i.e., that species with stylar movements that ensure self-pollination, or that possess cleistogamous flowers, are in fact self-compatible; and that dioecious species
One might expect that the two dioecious species
would be more closely related and therefore the genome sizes of these two species to be similar.
Since Clusia is a genus constituted predominantly by dioecious species
, this approach opens interesting possibilities.
When some male size classes escape fishing, we predict that the mean population size of sex-changing stocks will decrease proportionally less than the mean population size of dioecious species
experiencing the same fishing mortality.
Some of the best low pollen trees are the females of dioecious species
such as ash, poplar, willow, cedar, juniper, cottonwood, mulberry, osage orange, xylosma, yew, box elder, podocarpus, fringe tree, holly, pepper tree, smoke tree, coffee tree, sassafras and red maple.
Two features of gynodioecious systems, in particular, cause this to be a somewhat different problem than the question of frequency-dependent fitness and sex ratio evolution in dioecious species
. First, hermaphrodites can transmit genes through both male and female function, whereas male steriles can only transmit genes through the female function.