Effect of Temperature and Parental Age on Fecundity and Offspring Fitness
The elder the parents and the higher the temperature the less fitness offspring in Drosophila melanogaster flies.
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- [00:00:01.260]Hi. My name is Nicole Acosta.
- [00:00:01.700]I am a biochemistry senior and today I am going to talk
- [00:00:04.800]about my UCARE project,
- [00:00:06.150]which is about the effect of temperature
and parental age on fecundity and offspring
- [00:00:10.410]fitness. So I have been working
with Dr. Montooth ... with Dr.
- [00:00:15.000]Montooth at her lab for over
a year and a half.
- [00:00:19.250]I always wanted to know all the data
we collect is then turned into graphs
- [00:00:24.080], and curves.
- [00:00:25.670]And all of these figures are then used
- [00:00:30.620]to do predictions and all of this.
- [00:00:33.830]So I wanted to know more
about the process. Um,
- [00:00:36.680]this is one of the reasons why I decided
to do my project in, in this area.
- [00:00:41.570]So we worked with Drosophila melanogaster
flies. These are ectothers,
- [00:00:45.650]meaning they cannot regulate
their own body temperature.
- [00:00:48.620]They depend on the environmental
temperature since global warming is,
- [00:00:53.720]um, altering the mean and
variance of environment temperature,
- [00:00:58.790]this place will be affected
by that. So, yep. At the right.
- [00:01:03.770]You can see a thermal performance curve,
- [00:01:06.380]and this is a quantitative way to measure
the effects of temperature on flies.
- [00:01:10.070]So there are three important
things about this graph.
- [00:01:13.580]The first one is the temperature optimum,
- [00:01:16.190]which is the temperature of which
flies will best perform. The breath,
- [00:01:19.880]temperature breathd, and the criticals
minimum and maximum temperature.
- [00:01:25.280]My objectives.
- [00:01:26.420]The first one is to evaluate reproductive
fitness in response to a thermal
- [00:01:29.270]environment under a wide range
of contant temperatures.
- [00:01:31.600]Second one model thermal performance
curves of reproductive fitness. And determine
- [00:01:36.380]the effect of age of
- [00:01:39.850]Assess impacts of parental age on offspring development survivorship.
- [00:01:43.370]Analyze interaction between parental
age and temperature on the reproduction
- [00:01:47.510]and offspring developmentl survivorship. Methods are divided into two.
- [00:01:52.460]The first part is experimental
design and the data collection.
- [00:01:55.670]And the second part is the
analysis of the data. So the,
- [00:01:59.990]so for the main population, uh,
- [00:02:04.880]flies were cut from here,
Lincoln, Nebraska, okay. The,
- [00:02:09.850]the flights were kept
at 22 degrees Celsius.
- [00:02:12.470]Each generation of newly emerged flights
were reared in plastic bottles to keep
- [00:02:16.580]an breeding population and
genetic variation, cohorts
from different bottles were
- [00:02:21.470]mixed every generation.
- [00:02:21.740]After 12 generations,
flies from this main population were
- [00:02:26.570]kept into egg collection cages
with agar plates. Flies,
- [00:02:30.590]lay the eggs in the agar plates,
and we can easily collect the eggs.
- [00:02:35.300]So we collect 30 eggs and
place them on a new agar plate.
- [00:02:41.210]And these eggs were kept
at a determined temperature,
- [00:02:45.830]as you can see in the diagram.
- [00:02:48.350]So we have four cohort per
temperature, and each cohort,
- [00:02:55.130]have 30 eggs.
- [00:03:00.040]Eggs were kept until the emerged to
adults. And once they are,
- [00:03:03.670]they were adult we kept a female
and three males on the same vial.
- [00:03:08.860]We transferred them, the flies,
every day. Uh, the old vial,
- [00:03:13.390]we come to the eggs and
we kept the via until
- [00:03:19.770]the adults emerged.
- [00:03:21.270]We count the females and we count the males that emerged
- [00:03:26.280]from these eggs.
- [00:03:28.770]This is part of the experimental
design. So for the analysis,
- [00:03:33.420]we modeled the TPC curve of female
reproductive fitness using the nonlinear
- [00:03:38.100]thermodynamic pross-based model Sharpe.
- [00:03:41.910]We with the TPC group with TPC,
- [00:03:44.640]we determine the optimum
temperature, standard breathd,
- [00:03:48.660]tolerance rates range,
and activation energy.
- [00:03:52.140]We also analyze temperature by
age interaction effects on reproduction
- [00:03:57.120]using different types of
regression included linear model,
- [00:04:00.360]linear mixed models, generalized
linear model and generalized lineal mixed model.
- [00:04:06.300]So for results here,
you can see that eggs, uh,
- [00:04:11.160]eggs offspring, the eggs and the
adults, uh, different temperatures.
- [00:04:15.060]As you can see, 22 where the
flies that lay more eggs,
- [00:04:17.940]as well as they flies that produce more adults, uh,
- [00:04:22.920]31 eggs are about 300. However, that is,
- [00:04:25.980]you cannot see that much
of adults are temperature 31,
- [00:04:31.260]meaning the, there is a high mortality
between eggs and adults at this,
- [00:04:35.940]uh, temperature. Here you can see the
thermal performance gear that you can see,
- [00:04:41.340]temperature optimum is 23.4,
four eggs and 23.2 for adults.
- [00:04:46.530]Um, the temperature
breathd, which is, uh, at,
- [00:04:50.640]in this case is 80,
- [00:04:52.710]meaning that this is the temperature
range at which 80%
- [00:04:57.510]of the population will succeed for eggs
- [00:05:02.460]eggs, which is, uh, on your left.
- [00:05:04.770]It is between 18.5 and
26.8 degrees Celsius.
- [00:05:08.850]And for adults, which
is, and you're right,
- [00:05:11.760]it is between 18.5 and 25.9.
- [00:05:16.740]And temperature critical temperatures are
- [00:05:21.240]6.8 to 34.8,
- [00:05:24.270]for eggs. And 9.1 and
- [00:05:28.110]32.0 for adults.
- [00:05:32.490]So this will be their range
at which they will, uh,
- [00:05:35.700]the critical minimum and
maximum for this flies.
- [00:05:41.130]So here we see the relationship between
number of offspring and parental
- [00:05:45.930]age, as well as temperature.
So you can see here,
- [00:05:49.620]there is a lot of eggs
- [00:05:55.110]At high temperatures, females lay more eggs. However,
- [00:05:59.570]they have a shorter lifespan,
as you can see here as well. Um,
- [00:06:04.550]the lower, the temperature,
the longer the lifespan. Uh,
- [00:06:07.760]we also notice that the
- [00:06:11.450]at 17.5 degrees Celsius,
- [00:06:13.610]they have a higher reproductive output
that at 16 degrees Celsius, uh,
- [00:06:17.960]even the 16 is a lower
temperature than, 17.5. So, um,
- [00:06:22.580]These are the important, um, important
parts parts of these graphs.
- [00:06:28.160]Here, we see the average survivorship,
- [00:06:31.940]as you can see at 18 was when
- [00:06:39.160]the survivorship was higher. At 31
- [00:06:41.380]it was lower as we already see
also in the first set of results in
- [00:06:46.300]the right.
- [00:06:46.660]You see that 17.5 was the temperature that
- [00:06:51.490]has the higher survivorship. And, uh,
- [00:06:56.110]at higher temperatures like 22, sorry,
- [00:06:58.650]28 and 25 parents did not.
- [00:07:02.680]Parents have short lifespan and, uh,
- [00:07:05.200]they have not had as high survivorship
as lower temperatures.
- [00:07:09.460]Here we have linear mixed models and
generalized linear mixed models for
- [00:07:14.020]a eggs. As you can see,
- [00:07:16.450]16 have a longer lifespan for both graphs
- [00:07:21.520]and the higher, the temperature,
the shorter, the lifespan,
- [00:07:25.660]In conclusion,
- [00:07:26.560]environmental conditions like temperature,
shape the relationship between parental age
- [00:07:30.220]and offspring fitness. So
we know about the relationship.
- [00:07:33.730]We know that the
older the parents, fewer eggs. The higher
- [00:07:37.900]the temperature fewer
eggs, but we don't know why.
- [00:07:41.620]So that will be a good area for
research for future
- [00:07:47.140]uh, investigations. Uh, thank
you. Thank you Dr. Montooth, Dr.
- [00:07:51.550]Roston and Dr. Ibrahim, for
being part of this process.
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