Bat work manual 26 (3791)


Reproductive status of males



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5.2.3 Reproductive status of males
Testicular descent
The position of the testes varies among the families of bats. In many Microchiroptera they are descended at birth and lie close to and on either side of the base of the penis, where they form bulges beneath the skin. Several authors have referred to seasonal testicular descent corresponding with seasonal spermatogenesis, but this has not been recorded in British bats.
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Handling a greater horseshoe bat. © Frank Greenaway


Puberty and spermatogenesis
Puberty is reached inmost bats in the year following birth. However, in some vespertilionids some individuals achieve sexual maturity in their first autumn, while some horseshoe bats become sexually mature only after several years.
Both testes and epididymides are covered with a sheath of peritoneum - the tunica vaginalis. In juvenile and sexually immature male vespertilionids the tunica round the cauda epididymidis (= tail of the epididymis) can typically be seen through the skin as a densely pigmented sheath (figure a. Increase in the size of the testes, associated with growth of the seminiferous tubules and spermatogenesis, can be seen through the skin. After their release from the testes, spermatozoa pass through the epididymides to the caudae, which become distended between the layers of skin forming the interfemoral membrane.
The rapid shrinkage of the testes at the end of spermatogenesis and the correspondingly rapid swelling of the caudae is very striking in captive bats. As a result of this swelling, the tunica vaginalis over the epididymis becomes stretched and the black pigment cells (melanocytes) separate so that the distended epididymal tubules appear white through the skin (figure b. After this initial separation has occurred, the melanocytes seldom return to their former density (in pipistrelles), so the apparent reduction in pigmentation, accompanied by varying degrees of distension of the epidydimis,
can be used as a criterion of sexual maturity
(although this is not proven in all genera. Where testicular swelling is apparent but the cauda is still heavily pigmented, the individual is probably undergoing its first spermatogenesis and is therefore described as pubertal.
Not only do immature bats have pigmented tunicae,
but their testes are also smaller than those of individuals that have experienced spermatogenesis.
This maybe seen when the testes are examined through the skin.
The distinction between those males that have lost most of their epididymal spermatozoa and immature individuals is complicated when fat is deposited within the tunica vaginalis around the convoluted tubule of the epididymis and causes this membrane to appear stretched. In very fat hibernating bats, both testes and epididymis maybe completely obscured from view.


Health and safety in bat work
Catching bats
Ringing and marking
Public relations
Conserving and creating bat roosts
Forewordbat
Bat workers manual 09acknowledgements
Bats and the law
Law enforcement – gathering evidence
Convention on the conservation of
Public inquiry confirms importance of lesser horseshoe bat roost
Taking bats into captivity
Advice to the public who find grounded bats
Advice on bats and rabies
Dust and insulation
Wasp, bee and hornet nests
Survey and monitoring
Day surveys of potential roost structures
Case study – bats in barns survey
Case study – the bats in churches project
Identification
Bats and echolocation
Bat detectors
Basic equipment required:
Sonogram analysis
Extraction from hand-nets
Figure 4.1hand-nets. polythene around the lip prevents bats climbing out.figure 4.3
Single-pole flicking
Chapter 4 c atching bats44two-pole flicking
Chapter 4 c atching bats463
Chapter 5 examining bats50figure 5.1
Parturition and lactation
Fur colour and texture
Wing span, and head and body length
Mites, including ticks (acari)
Bat-bugs (hemiptera, cimicidae)
Fleas (siphonaptera, ischnopsyllidae)
Bat-flies (diptera, nycteribiidae)
Rabies surveillance
Chapter 5 examining bats56sending dead bats by post
References and further reading
Handling, releasing and keeping bats
Moral considerations
Adultstemporary debility or injury likely to heal
Permanent captives
Bat conservation trust - guidelines on bats in captivity
Insects and substitutes
Vitamins and minerals
Weaning and rearing orphaned bats
The role of a bat group
The bat conservation trust
Bats on the internet
Bats in the living area
General fear of bats
Damage to buildings
Transmission of disease
Interior design fora huge roost of (smelly) bats
Legal position (simplified)
Outside the breeding season
Insects in droppings
Speciesnumber of roosts
Summary – exclusion of bats
Summary – visit to householders who have discovered bats
Security alarm systems in buildings
Timber treatment, pest control
During breeding season
If bats are torpid
Fungicidescommon name
If bats are active
Outside breeding season
Fusible link shutters
Case study - window and lintel replacement
Case study - roof refurbishment
Case study – timber treatment and roof renovation
Excessive disturbance
Destruction, maintenance or change of use
Chapter 11 conserving and creating bat roosts112figure 11.1
Grade b sites without protection.
Grade 4 (many sites)
Grade 1 (fewer than 10 sites)
Railway tunnel enhancement
Cave construction
Manipulation of airflow and temperature
Reopening of blocked sites
Provision of additional roosting points
Chapter 11 conserving and creating bat roosts122figure 11.5
Figure 11.5 (continued)
Converting a pillbox for bats
Bat conservation code
Wildlife and countryside act 1981 &
Tree preservation orders
Maintaining roosts
Creating roosts
Case histories of bridge maintenance works
Examples of roost creation within bridges
Appendix 1140figure a1.1
Appendix 1142figure a1.1
Appendix 3 9
Grid reference.
Biological records centre single species card
Monitoring methods
Hibernation counts
Bat speciessc
Appendix 4150participation and experience required
A selected bibliography
A european bats – identification,
C children’s books
Appendix 5154d journals, magazines and newsletters
Bat research news
Useful names and addresses
The environment and heritage service
Department for environment, food and rural
Non governmental organisations
National association of mining history
The national trust
Subterranea britannica
Equipment suppliers
Pettersson elektronik ab
Bernies cafe and caving supplies
Watkins and doncaster
Holohil systems ltd
Titley electronics
Jacobi jayne & co
Mealwormslive foods direct ltd
Bat workers training syllabus
Circumstances requiring consultation
Licensinglicensable activities
Appendix 7164other licences
Bat biology and ecology
Basic ecology
Bat conservation
Persecution and intolerance
Presenting bats to the public
Safety underground
Appendix 7168training checklist
Model risk assessment for entry into disused mines (cont)
Model risk assessment for initial entry into derelict and dilapidated buildings and structures
Model risk assessment for initial entry into derelict and dilapidated buildings and structures (cont)
Model risk assessment for entry into confined spaces
Model risk assessment for entry into confined spaces (cont)
Health and safety at work etc act 1974
Health and safety legislation
The carriage of dangerous goods
References legislation
Appendix 9178for laboratory use only



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