Detecting Cryptic Female Choice in Decapod Crustaceans

2020 ◽  
pp. 364-393
Author(s):  
Colin L. McLay ◽  
Stefan Dennenmoser
Keyword(s):  
Female Choice ◽  
Field Data ◽  
Seminal Receptacle ◽  
Multiple Paternity ◽  
Mate Guarding ◽  
Cryptic Female Choice ◽  
Mating History ◽  
Decapod Crustacea ◽  
Hard Shell ◽  
Male Mate

Decapod Crustacea (shrimps, lobsters, and crabs) employ a range of different reproductive mechanisms that affect paternity, but does it include cryptic female choice (CFC)? This chapter focuses on events surrounding the fertilization of an egg by a sperm and the opportunities where cryptic fertilization bias might occur. It presents a new model of decapod fertilization, defined in terms of space and time to fertilization. Females have several ways to store sperm and influence fertilization outcomes, which should be affected by (1) their growth pattern (indeterminate or determinate), (2) the link between molting and mating (soft-shell or hard-shell mating), (3) fertilization latency, and (4) how sperm are protected (no protection or storage is separate from the oviduct, or storage in a seminal receptacle is linked to the oviduct). Paternity data available for 26 decapods show that in 85% of species, females carry broods with multiple paternity and 15% have broods with single paternity. Therefore many (if not most) females mate with several males and so they certainly could make a choice. However, whether this pattern is due to CFC or merely reflects mating history is a matter of debate. At present, there are no unequivocal data that demonstrate CFC: outcomes caused by male mate guarding and sperm competition cannot be distinguished from female choice. The challenge is to understand what females might be choosing and how to detect that choice. Detecting CFC in field data is difficult, if not impossible, because both single and multiple paternities could be favored.

Female control of paternity by spawning site choice in a cooperatively polyandrous cichlid

Behaviour ◽  
2015 ◽  
Vol 152 (2) ◽  
pp. 231-245 ◽  
Author(s):  
Ning Li ◽  
Tomohiro Takeyama ◽  
Lyndon Alexander Jordan ◽  
Masanori Kohda
Keyword(s):  
Female Choice ◽  
Multiple Paternity ◽  
Cichlid Fish ◽  
Cryptic Female Choice ◽  
Mating Partner ◽  
Spawning Site ◽  
Direct Benefits ◽  
Nest Design ◽  
Narrow Area ◽  
Female Control

Multiple mating of females is widespread, and females often obtain direct and/or indirect benefits by mating with multiple males. However, female control of multiple paternity broods is usually only possible in internally fertilising animals with complex reproductive systems including cryptic female choice. Here we present direct evidence that a cooperative polyandrous cichlid fish with external fertilisation, Julidochromis transcriptus, uses environmental factors to manipulate male access to, and therefore paternity of, their egg clutches. Polyandrous females receive more paternal investment from both of large alpha males and small beta males than monogamous females. We used a ‘step nest’ design, in which large alpha males and small beta males were restricted to the wide and narrow nest areas respectively, and found that when kept in polyandrous trios, females laid their egg clutches exactly at the borderline between the two regions each male could access. In contrast, females in pairs laid their clutches in either the wide or narrow area depending on the size of their mating partner. Our results demonstrate that polyandrous females carefully choose egg deposition site, increasing the direct benefits they receive from mating partners by using environmental structures to manipulate paternity. In this way, externally fertilising J. transcriptus manipulate male behaviour in a manner similar to cryptic female choice in internally fertilising animals.

Post-Copulatory Sexual Selection

2021 ◽  
Author(s):  
Patricia L.R. Brennan ◽  
Dara N. Orbach
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Female Choice ◽  
Reproductive Tract ◽  
Seminal Fluid ◽  
Fertilization Success ◽  
Female Reproductive Tract ◽  
Cryptic Female Choice ◽  
Trade Offs ◽  
Morphological Criteria

The field of post-copulatory sexual selection investigates how female and male adaptations have evolved to influence the fertilization of eggs while optimizing fitness during and after copulation, when females mate with multiple males. When females are polyandrous (one female mates with multiple males), they may optimize their mating rate and control the outcome of mating interactions to acquire direct and indirect benefits. Polyandry may also favor the evolution of male traits that offer an advantage in post-copulatory male-male sperm competition. Sperm competition occurs when the sperm, seminal fluid, and/or genitalia of one male directly impacts the outcome of fertilization success of a rival male. When a female mates with multiple males, she may use information from a number of traits to choose who will sire her offspring. This cryptic female choice (CFC) to bias paternity can be based on behavioral, physiological, and morphological criteria (e.g., copulatory courtship, volume and/or composition of seminal fluid, shape of grasping appendages). Because male fitness interests are rarely perfectly aligned with female fitness interests, sexual conflict over mating and fertilization commonly occur during copulatory and post-copulatory interactions. Post-copulatory interactions inherently involve close associations between female and male reproductive characteristics, which in many species potentially include sperm storage and sperm movement inside the female reproductive tract, and highlight the intricate coevolution between the sexes. This coevolution is also common in genital morphology. The great diversity of genitalia among species is attributed to sexual selection. The evolution of genital attributes that allow females to maintain reproductive autonomy over paternity via cryptic female choice or that prevent male manipulation and sexual control via sexually antagonistic coevolution have been well documented. Additionally, cases where genitalia evolve through intrasexual competition are well known. Another important area of study in post-copulatory sexual selection is the examination of trade-offs between investments in pre-copulatory and post-copulatory traits, since organisms have limited energetic resources to allocate to reproduction, and securing both mating and fertilization is essential for reproductive success.

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