The Reproductive Strategy of a Parasitic Wasp: I. Optimal Progeny and Sex Allocation in Trichogramma evanescens

10.2307/4524 ◽  
1984 ◽  
Vol 53 (2) ◽  
pp. 401 ◽  
Author(s):  
Jeffrey K. Waage ◽  
Ng Sook Ming
Keyword(s):  
Reproductive Strategy ◽  
Sex Allocation ◽  
Parasitic Wasp ◽  
Trichogramma Evanescens

scholarly journals Effects of host and foundress density on reproductive strategy of Diaeretiella rapae

2012 ◽  
Vol 65 ◽  
pp. 294-294 ◽  
Author(s):  
R. Kant ◽  
M.A. Minor ◽  
S.A. Trewick ◽  
W.R.M. Sandanayaka
Keyword(s):  
Sex Ratio ◽  
Reproductive Strategy ◽  
Sex Allocation ◽  
Parasitic Wasp ◽  
Female Offspring ◽  
Reproductive Fitness ◽  
Brevicoryne Brassicae ◽  
Diaeretiella Rapae ◽  
Progeny Production ◽  
Total Parasitism

The reproductive fitness of a parasitoid depends on the oviposition decisions of a female in response to competition The present study investigated the oviposition and sex ratio of offspring produced by the parasitic wasp Diaeretiella rapae while competing with other conspecific females and at different host densities The number of Brevicoryne brassicae nymphs parasitised by female D rapae increased with the number of nymphs offered to them However the proportion of nymphs parasitised by the female decreased when nymph density was high The proportion of fertilised eggs oviposited by females decreased when nymph density increased An increase in the number of foundresses (females ovpositing together) increased the total parasitism but the contribution of each female (the number of nymphs each female parasitised) decreased Smaller proportions of female offspring were produced when females were competing for the same hosts The results of this study suggest that both host and foundress densities asymmetrically affect progeny production and sex allocation in this species

scholarly journals Effects of Isometric Brain-Body Size Scaling on the Complexity of Monoaminergic Neurons in a Minute Parasitic Wasp

2017 ◽  
Vol 89 (3) ◽  
pp. 185-194 ◽  
Author(s):  
Emma van der Woude ◽  
Hans M. Smid
Keyword(s):  
Body Size ◽  
Cognitive Abilities ◽  
Brain Volume ◽  
Brain Size ◽  
Parasitic Wasp ◽  
Body Volume ◽  
Neural Pathways ◽  
Trichogramma Evanescens ◽  
Monoaminergic Neurons ◽  
Large Animals

Trichogramma evanescens parasitic wasps show large phenotypic plasticity in brain and body size, resulting in a 5-fold difference in brain volume among genetically identical sister wasps. Brain volume scales linearly with body volume in these wasps. This isometric brain scaling forms an exception to Haller's rule, which states that small animals have relatively larger brains than large animals. The large plasticity in brain size may be facilitated by plasticity in neuron size, in the number of neurons, or both. Here, we investigated whether brain isometry requires plasticity in the number and size of monoaminergic neurons that express serotonin (5HT), octopamine (OA), and dopamine (DA). Genetically identical small and large T. evanescens appear to have the same number of 5HT-, OA-, and DA-like immunoreactive cell bodies in their brains, but these cell bodies differ in diameter. This indicates that brain isometry can be facilitated by plasticity in the size of monoaminergic neurons, rather than plasticity in numbers of monoaminergic neurons. Selection pressures on body miniaturization may have resulted in the evolution of miniaturized neural pathways that allow even the smallest wasps to find suitable hosts. Plasticity in the size of neural components may be among the mechanisms that underlie isometric brain scaling while maintaining cognitive abilities in the smallest individuals.

Reproductive strategies in hermaphroditic gastropods: conceptual and empirical approaches

2013 ◽  
Vol 91 (6) ◽  
pp. 367-381 ◽  
Author(s):  
Yumi Nakadera ◽  
Joris M. Koene
Keyword(s):  
Sexual Selection ◽  
Reproductive Success ◽  
Experimental Research ◽  
Reproductive System ◽  
Reproductive Strategy ◽  
Reproductive Strategies ◽  
Sex Allocation ◽  
Fitness Consequences ◽  
The Individual ◽  
Empirical Approaches

An individual optimizes its reproductive success by adopting a particular reproductive strategy. Studying the details of a reproductive strategy leads to an understanding of how sexual selection acts, as the former is the process via which the individual reproduces successfully. Hermaphroditic gastropods display a bewildering diversity of reproductive strategies, which may be due to their mode of gender expression, when compared with well-studied separate-sexed species. Extensive theoretical, observational, and experimental research has been conducted on this topic. However, despite our knowledge about the reproductive system of hermaphroditic gastropods, we still need to fill the gap between pre- and post-copulatory processes and reproductive success. Here, we review and propose conceptual and empirical approaches aimed at understanding reproductive strategies of hermaphroditic gastropods. In sum, our suggestions are (i) to focus on sex-biased traits, (ii) to take biologically reliable measurements at both the pre- and post-copulatory level that relate to reproductive success, and (iii) to examine the fitness consequences of biased sex allocation.

scholarly journals Nasonia Parasitic Wasps Escape from Haller's Rule by Diphasic, Partially Isometric Brain-Body Size Scaling and Selective Neuropil Adaptations

2017 ◽  
Vol 90 (3) ◽  
pp. 243-254 ◽  
Author(s):  
Jitte Groothuis ◽  
Hans M. Smid
Keyword(s):  
Body Size ◽  
Brain Size ◽  
Parasitic Wasp ◽  
Volumetric Analysis ◽  
Relative Volume ◽  
Trichogramma Evanescens ◽  
Size Scaling ◽  
Relative Brain Size ◽  
Brain Architecture ◽  
Size Relation

Haller's rule states that brains scale allometrically with body size in all animals, meaning that relative brain size increases with decreasing body size. This rule applies both on inter- and intraspecific comparisons. Only 1 species, the extremely small parasitic wasp Trichogramma evanescens, is known as an exception and shows an isometric brain-body size relation in an intraspecific comparison between differently sized individuals. Here, we investigated if such an isometric brain-body size relationship also occurs in an intraspecific comparison with a slightly larger parasitic wasp, Nasonia vitripennis, a species that may vary 10-fold in body weight upon differences in levels of scramble competition during larval development. We show that Nasonia exhibits diphasic brain-body size scaling: larger wasps scale allometrically, following Haller's rule, whereas the smallest wasps show isometric scaling. Brains of smaller wasps are, therefore, smaller than expected and we hypothesized that this may lead to adaptations in brain architecture. Volumetric analysis of neuropil composition revealed that wasps of different sizes differed in relative volume of multiple neuropils. The optic lobes and mushroom bodies in particular were smaller in the smallest wasps. Furthermore, smaller brains had a relatively smaller total neuropil volume and larger cellular rind than large brains. These changes in relative brain size and brain architecture suggest that the energetic constraints on brain tissue outweigh specific cognitive requirements in small Nasonia wasps.

Constrained oviposition and female-biased sex allocation in a parasitic wasp

Oecologia ◽  
1997 ◽  
Vol 109 (4) ◽  
pp. 547-555 ◽  
Author(s):  
P. J. Ode ◽  
Michael F. Antolin ◽  
Michael R. Strand
Keyword(s):  
Sex Allocation ◽  
Parasitic Wasp
Sign in / Sign up

Export Citation Format

Share Document